Sometimes you come across an email with text that is so small that it is difficult to read. Instead of struggling to read it, you can increase the font size to make it easier to read. Apple Mac OS X and macOS Mail offer a number of ways to display an email in a larger font.
Set font size in Apple Mail
With just one keyboard shortcut, you can read an email in a larger font in Mac OS X and macOS Mail:
Open the Mail app on your Mac and click on an email message to open it in the preview pane. This is the large area where you can see the entire message.
Press the Command++ keyboard shortcut (the plus key) to enlarge the contents of the preview pane, including the email text. Repeat the shortcut as many times as you like. The text will become larger each time.
