Login into your GMail account.

Select "Settings" in the upper right corner of the page.

Setting screen will appear with General tab selected
Scroll down to Signature.

Select the radio button beside the empty text box and Type the information you wish to have in your signature in the empty text box.

Scroll futher down the page until you see the Save Changes button.

Click the "Save Changes" to confirm your signature.

GMail goes back to your Inbox.

That was pretty easy. Now to test if it worked.

Test Email Signature in GMail

1. Now that you have a signture set up you should test that it is working and looking the way you wanted it to.
2. From your Inbox, click the Compose Mail link in the top left.
3. A new screen will appear with an empty new email and your signature included
4. Did you notice, your signature was automatically inserted.
5. If you feel you need to revise your signature, just go back to Settings and repeat the process above.

Now each email will contain the information on how to contact you when sending Gmail when you email your friends!