Email, Messaging, & Video Calls > Email Changing the Default Mozilla Thunderbird Message Font Adjust the size, color, and style of your message text By Heinz Tschabitscher Heinz Tschabitscher Writer University of Vienna A former freelance contributor who has reviewed hundreds of email programs and services since 1997. lifewire's editorial guidelines Updated on April 12, 2021 Reviewed by Jerrick Leger Reviewed by Jerrick Leger Jerrick Leger is a CompTIA-certified IT Specialist with more than 10 years' experience in technical support and IT fields. He is also a systems administrator for an IT firm in Texas serving small businesses. lifewire's editorial guidelines Tweet Share Email Tweet Share Email Email Yahoo! Mail Gmail What to Know Go to Menu > Account Settings > Composition & Addressing and make sure Compose messages in HTML format is checked.Next, select Global Composing Preferences, choose General, then scroll down to Language & Appearance to adjust the font.To change the font when composing a message, select Format > Font. This article explains how to change the default font in Mozilla Thunderbird for composing new messages. The instructions below apply to Thunderbird for Windows, but the process is similar on Macs. Change the Default Mozilla Thunderbird Message Font To set your own default font for composing new messages in Mozilla Thunderbird: Select the menu icon (the three lines) in the upper-right corner, then select Account Settings. Select Composition & Addressing under your email address in the left sidebar. Make sure the Compose messages in HTML format box is checked, then select Global Composing Preferences. Select General in the left sidebar, then scroll down to Language & Appearance to adjust the default font and text size. Select Advanced under Fonts & Colors for more options, including fonts for different languages. Close the Thunderbird settings windows. The change takes effect the next time you compose a message. It's also possible to change the font for incoming mail in Thunderbird if you want to make your messages easier to read. Change the Font in Thunderbird Messages To change the font for an individual email, compose your message and select Format > Font. Was this page helpful? Thanks for letting us know! Get the Latest Tech News Delivered Every Day Email Address Sign up There was an error. Please try again. You're in! Thanks for signing up. There was an error. Please try again. Thank you for signing up! Tell us why! Other Not enough details Hard to understand Submit