Select theFonts & Colorstab in the preferences screen.

Next toMessage font, clickSelect.

In the Fonts screen that opens, grab the desired font in theFamilycolumn.

Path to Mail Preferences on Mac

Choose a variant in theTypefacecolumn and pick a font size in theSizecolumn.

Click theComposingtab in the preferences screen.

In theComposingsection, confirm thatRich Textis selected next toMessage Format.

Fonts & Colors preferences tab in Mac Mail preferences

Select it if it is not chosen.

Optionally, in theRespondingsection, checkUse the same message format as the original message.

When people send you plain text messages, your replies are in plain text as well.

Fonts & Colors preferences screen for Mac Mail

Your default font is not used.

wrap up the preferences window.

pop in the email text and then highlight the part of the text you want to change.

Fonts screen in Mac Mail preferences showing font options

What Makes a Good Font for Email?

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.

Composing preferences for Mac Mail

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.

Composing screen with Rich Text selected for Message Format

Changing fonts in Mac Mail emails