In the following tutorial you will learn how to create a simple mail icon. We’ll work from basic shapes and use the Pathfinder panel and Gradients to create a stylish icon in Adobe Illustrator.
Step 1
Open Illustrator and hit Command + N to create a new document. Enter 600 in the width and height boxes then click on the Advanced button. Select RGB, Screen (72ppi) and make sure that the "Align New Objects to Pixel Grid" box is unchecked before your click OK. Enable the Grid (View > Show Grid) and the Snap to Grid (View > Snap to Grid).
Next, you’ll need a grid every 5px. Simply go to Edit > Preferences > Guides & Grid, enter 5 in the Gridline every box and 1 in the Subdivisions box. You can also open the Info panel (Window > Info) for a live preview with the size and position of your shapes. Do not forget to set the unit of measurement to pixels from Edit > Preferences > Unit > General. Al these options will significantly increase your work speed.

Step 2
Using the Rectangle Tool (M), create a 200 by 125px shape, fill it with the linear gradient shown in the following image and go to Effect > Stylize > Rounded Corners. Enter a 10px radius, click OK and go to Object > Expand Appearance.

Step 3
Reselect the shape made in the previous step and make a copy in front (Control + C > Control + F). Using the Rectangle Tool (M), create a 220 by 95px shape, fill it with R=119 G=154 B=99 and place it as shown in the second image. Focus on the top side of this green rectangle and switch to the Direct Selection Tool (A). Select the two anchor points (highlighted in the second image) and go to Object > Path > Average (Alt + Control + J). Check the Both button and click OK. This should turn your green rectangle into a triangle. Select it along with the copy made in the beginning of the step, open the Pathfinder panel and click on the Intersect button. In the end your green shape should look like in the fourth image.

Step 4
Disable the Snap to Grid (View > Snap to Grid) then go to Edit > Preferences > General and make sure that the Keyboard Increment is set at 1px. Select the green shape made in the previous step and make two copies in front (Control + C > Control + F > Control + F). Move to the Layers panel, select the bottom copy and move it 2px up using the up arrow from your keyboard. Reselect both copies made in this step and click on the Minus Front button from the Pathfinder panel. Focus on the resulting shape, grab the Delete Anchor Point Tool (-) and remove the two anchor points pointed by the arrows in the third image. Fill this thin shape with the linear gradient shown in the final image then lower its Opacity to 15% and change the Blending Mode to Multiply. The yellow number ("55") from the gradient image stands for Opacity percentage.

Step 5
Select the green shape and go to Object > Path > Offset Path. Enter a -1px Offset and click OK. Select the resulting shape and make a copy in front (Control + C > Control + F). Select this copy and move it 1px up using the up arrow from your keyboard. Reselect both shape made in this step and click on the Minus Front button from your keyboard. Fill the resulting shape with the linear gradient shown in the following image. Remember that the yellow zeros from the gradient image stand for Opacity percentage.

Step 6
Reselect the rounded rectangle made in the second step and make two copies in front (Control + C > Control + F > Control + F). Select the top copy and move it 1px up. Reselect both copies and click on the Minus Front button from the Pathfinder panel. Select the resulting shape, bring it to front (Shift + Control + ] ), fill it with the linear gradient shown in the following image and change its Blending Mode to Soft Light.

Step 7
Reselect the green shape and replace the flat color used for the fill with the linear gradient shown in the following image. The white number ("50") from the gradient image stands for location percentage.

Step 8
Enable the Snap to Grid (View > Snap to Grid). Reselect the rounded rectangle made in the second step and make a copy in front (Control + C > Control + F). Using the Rectangle Tool (M), create a 220 by 80px shape, fill it with R=119 G=154 B=99 and place it as shown in the second image. Focus on the bottom side of this green rectangle and switch to the Direct Selection Tool (A). Select the two anchor points (highlighted in the second image) and go to Object > Path > Average (Alt + Control + J). Check the Both button and click OK. Select the resulting triangle along with the copy made in the beginning of the step and click on the Intersect button from the Pathfinder panel. In the end your green shape should look like in the fourth image.

Step 9
Disable the Snap to Grid (View > Snap to Grid). Select the green shape made in the previous step and make two copies in front (Control + C > Control + F > Control + F). Select the top copy and move it 2px up using the up arrow from your keyboard. Reselect both copies and click on the Minus Front button from the Pathfinder panel.
Focus on the resulting shape, grab the Delete Anchor Point Tool (-) and remove the two anchor points pointed by the arrows in the third image. Finally, fill this sharp shape with the linear gradient shown in the following image.

Step 10
Reselect the green shape and make two copies in front (Control + C > Control + F > Control + F). Select the top copy and move it 1px down. Reselect both copies and click on the Minus Front button from the Pathfinder panel. Fill the resulting shape with the linear gradient shown in the third image, lower its Opacity to 50% and change the Blending Mode to Soft Light.

Step 11
Reselect the green shape and make a copy in front (Control + C > Control + F). Select it, move it 1px down then duplicate it (Control + C > Control + F). Select this second copy and move it 1px down. Reselect both copies and click on the Minus Front button from the Pathfinder panel. Fill the resulting shape with the linear gradient shown in the following image.

Step 12
Select the green shape and make two copies in front (Control + C > Control + F > Control + F). Move to the Layers panel, select the bottom copy and move it 1px down using the down arrow from your keyboard. Reselect both copies made in this step and click on the Minus Front button from the Pathfinder panel. Focus on the resulting shape, grab the Delete Anchor Point Tool (-) and remove the two anchor points pointed by the arrows in the third image. Finally, fill this sharp shape with the linear gradient shown in the following image, lower its Opacity to 10% and change the Blending Mode to Multiply.

Step 13
Enable the Snap to Grid (View > Snap to Grid). Using the Rectangle Tool (M), create a 180 by 75px shape, fill it with R=173 G=149 B=116 and place it as shown in the first image. Focus on the bottom side of this brown rectangle and switch to the Direct Selection Tool (A). Select the two anchor points (highlighted in the first image) and go to Object > Path > Average (Alt + Control + J). Check the Both button and click OK. Move to the Layers panel, select this brown triangle, lower its Opacity to 15%, drag it below the green shape and go to Effect > Blur > Gaussian Blur. Enter a 4px radius and click OK.

Step 14
Reselect the green shape and replace the flat color used for the fill with the linear gradient shown in the following image.

Step 15
Disable the Snap to Grid (View > Snap to Grid). Reselect the rounded rectangle made in the second step and go to Object > Path > Offset Path. Enter a -1px Offset and click OK. Select the resulting shape and make a copy in front (Control + C > Control + F). Select this copy and move it 1px to the left. Reselect both shapes made in this step and click on the Minus Front button from the Pathfinder panel. Fill the resulting shape with the linear gradient shown in the following image.

Step 16
Reselect the rounded rectangle made in the second step and go to Object > Path > Offset Path. Enter a -1px Offset and click OK. Select the resulting shape and make a copy in front (Control + C > Control + F). Select this copy and move it 1px to the right. Reselect both shapes made in this step and click on the Minus Front button from the Pathfinder panel. Fill the resulting shape with the linear gradient shown in the following image.

Step 17
Select the rounded rectangle made in the second step, open the Appearance panel, add a second fill using the Add New Fill button (pointed by the little, blue arrow) and drag it in the bottom of the panel. Keep focusing on the Appearance panel, select this new fill, add the complex linear gradient shown in the following image and go to Effect > Distort & Transform > Transform. Enter the data shown below and click OK.

Step 18
Reselect the rounded rectangle made in the second step, add a third fill and drag it in the bottom of the Appearance panel. Select it, set the color at R=235 G=231 B=216 and go to Effect > Distort & Transform > Transform. Enter the data shown below and click OK.

Step 19
Reselect the rounded rectangle made in the second step, add two, black fills and drag them in the bottom of the Appearance panel. Select the top, black fill, lower its Opacity to 5% and go to Effect > Path > Offset Path. Enter a 1px Offset, click OK and go to Effect > Distort & Transform > Transform. Enter the data shown below and click OK. Select the bottom, black fill, lower its Opacity to 5% and go to Effect > Path > Offset Path. Enter a 1px Offset and click OK.

Step 20
Enable the Snap to Grid (View > Snap to Grid) and focus on the top, right corner of the envelope. Pick the Ellipse Tool (L), create a 45px circle, fill it with the linear gradient shown below, place it as shown in the first image and go to Object > Path > Offset Path. Enter a -1px Offset and click OK. Select the resulting shape, make a copy in front (Control + C > Control + F) and disable the Snap to Grid (View > Snap to Grid). Select this copy and move it 1px down. Reselect both smaller circles and click on the Minus Front button from the Pathfinder panel. Fill the resulting shape with R=255 G=104 B=109.

Step 21
Reselect the circle made in the previous step and go to Effect > Stylize > Drop Shadow. Enter the data shown in the left window, click OK and go again to Effect > Stylize > Drop Shadow. Enter the data shown in the right window and click OK. Make sure that this circle is still selected, focus on the Appearance panel and add a 1pt stroke. Align it to inside and set the color at R=135 G=30 B=45.

Step 22
Pick the Type Tool(T) and add a simple number as shown in the following image. Use the "American Purpose" font with the size set at 22pt. Select this little piece of text, focus on the Appearance panel and add two new fills using the Add New Fill button. Select the top fill and make it white then select the bottom fill, add the linear gradient shown in the following image, change the Blending Mode to Overlay and go to Effect > Path > Offset Path. Enter a 1px Offset, click OK and go to Effect > Stylize > Drop Shadow. Enter the data shown in the following image and click OK.

Step 23
For these final steps you will need a grid every 1px. So, go to Edit > Preferences > Guides & Grid and enter 1 in the Gridline every box. If you don’t like that simple circle you can easily replace it with a ribbon. Focus on the bottom, right corner of your envelope and using the Rectangle Tool (M), create a 50 by 10px shape, fill it with the linear gradient shown below. Place it as shown in the following image and go to Effect > Stylize > Rounded Corners. Enter a 5px radius and click OK. Select this rounded rectangle and send it to back (Shift + Control + [ ).

Step 24
Using the Rectangle Tool (M), create a 40 by 65px shape, fill it with the linear gradient shown below and place it as shown in the following image.

Step 25
Reselect the rectangle made in the previous step and go to Object > Path > Add Anchor Points. Switch to the Direct Selection Tool (A), select the top, middle anchor point and drag it 15px down. In the end your shape should look like in the second image.

Step 26
Reselect the shape made in the previous step, focus on the Appearance panel, select the fill and go to Effect > Warp > Shell Upper. Enter the data shown below, click OK and return to the Appearance panel. Add two, black fills and drag them in the bottom of the Appearance panel. Select the top, black fill, lower its Opacity to 15% and go to Effect > Distort & Transform > Transform. Enter the data shown below and click OK. Select the bottom, black fill, lower its Opacity to 25% and go to Effect > Path > Offset Path. Enter a -1px Offset, click OK and go to Effect > Distort & Transform > Transform. Enter the data shown below, click OK and go to Effect > Blur > Gaussian Blur. Enter a 2px radius and click OK.

Step 27
Reselect the shape edited in the previous step, focus on the Appearance panel and add two strokes using the Add New Stroke button (pointed by the little, blue arrow). Select the top stroke, make it 1pt wide, align it to inside, set the color at R=135 G=30 B=45, lower its Opacity to 80%, change the Blending Mode to Color Burn and go to Effect > Warp > Shell Upper. Enter the data shown below and click OK. Select the other stroke, make it 2pt wide, align to inside, set the color at white, lower its Opacity to 75%, change the Blending Mode to Overlay and go to Effect > Warp > Shell Upper. Enter the data shown below and click OK.

Step 28
Finally, duplicate that little piece of text added in the twenty-second step and place this copy as shown in the following image.

Conclusion
Now your work is done. Here is how it should look with both styles… ready to be used in your user interface designs.
