Create a GMAIL Signature
Click on the Cog and then select See All Settings. Under the General Tab, scroll down until you get to the signature section.
Select Create New and title your signature. Then type your Information for your Signature. You can change the font, size and color. Under the Signature Defaults, select the signature you just created as the default for the new emails. If you don't, you will have to add the signature each time you create a new email.
New Email - Change Font, Color
When you open a new email - this is what you see:
BUT if you want to have the option to change the font, font size or color, you have to expand the email. In order to do that, in the picture above click on the arrow in the middle (where the mint arrow is pointing) and it will expand the email. You will then be given more options.
Add GMAIL to Taskbar