On the Personal Stationery tab, under New mail messages or Replying or forwarding messages, choose Font. In the Font box, choose the font, style, size, and color that you want to use.

On the Personal Stationery tab, under New mail messages, click Font. If you want to change font styles for messages you reply to or forward, under Replying or forwarding messages, click Font.

In the Default fonts section select the Font button located next to the composition style you want to edit. For example, select Font next to New mail if you intend to specify a default text size for …

Increase or decrease the font size or choose a different font for items that appear in the message list.

Select the Font button for New mail messages or Replying or forwarding messages to change the default font, font size, and font color when composing or replying to messages.

Apply the latest Office Theme (font and colors) to your Microsoft 365 applications.

Learn how to change the font size when composing messages in Outlook on the web.

For example, you can quickly switch between day, week, or month views, or change your work week start day and time. You can also change your Outlook calendar’s font size and style, or …

If you have Write permissions and the default font setting still doesn't stick, you might have to turn off Word add-ins and change the default font setting. Here's how:

Depending on which style you want to change, right-click Followed Hyperlink or Hyperlink and pick Modify. In the Style box, click Format and on the Font tab, set your hyperlink font style …