Step 1: To create a signature, first open the Settings gear in the top right corner of the screen, and then go to Options.
Step 2: Then select Email Signature which is located towards the bottom on the left hand side of the screen.
Step 3: And then in the new window, enter your contact information and use the formatting options to make it look more professional if you please. And you can choose if you want your signature automatically added in messages. When you're done click Save.