How to Change Font in Gmail Messages Open Your Favorite Browser. Go to Gmail.com Enter your User name and Password. Click Sign in to Login to Your Gmail Account Click the Gear Icon in the Upper right corner of the page. Select Settings from the drop down menu. In the General Tab, Scroll Down to the “Default Text Style Section”. Here you can change the font, Font Size and Color. If you are not ok with the changes, you can remove the formatting by clicking on the last icon. After making the necessary changes, scroll down and click save changes. This is How You can Change Your Font in Gmail Messages.