Change the Default Mac Mail Font
To specify a default font face and size for composing and reading mail in the Mac macOS Mail application:
Changing a Mail Font on the Fly
Even if you establish a default font you want to use when composing emails, occasions may arise when you prefer using a different font for all or part of the email. Optionally, in the Responding section, check Use the same message format as the original message. When people send you plain text messages, your replies are in plain text as well. Your default font is not used. Type the email text and then highlight the part of the text you want to change. Format the selected text by selecting a font, size, color, or other attributes from the formatting bar at the top of the screen. Formatting changes are only available for the email message body, not for the To, From, and other header fields.
What Makes a Good Font for Email?
A good font for email is one that renders texts that are legible on any screen—a large monitor, tablet, phone, or watch. Typical font families that accomplish this are sans-serif fonts with little ambiguity between characters and ample height for small characters (x-height). Classics Verdana, Helvetica, and Arial are fonts that encompass these features and are almost universally available. Choose the size that makes your text big enough to be easily legible. Fonts between 11 and 13 points in size are typically suitable sizes for email. How the font displays on the recipient’s display depends on the recipient’s screen makeup and resolution. If they have size problems, they can enlarge the email type on a case-by-case basis or use assistive technology to increase the font’s display size permanently if necessary.
