In Microsoft Outlook for Windows, Mac, and the web, you can change the font and font size for specific emails as well as for all your emails. It's easy to make this change, and we'll show you how.
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Change the font and font size in Outlook for Windows and Mac
If you want to change the font and font size for a particular email, then first, launch that email in Outlook on your Windows or Mac. At the top of your email, in the “Message” tab, click the “Font” drop-down menu to select a new font. Similarly, click the “Font Size” drop-down menu to select a new size for the font you have selected.

To change the default font in Outlook on your Mac, launch the Outlook app and choose Outlook > Preferences > Fonts from the menu bar. Then, next to the email type for which you want to set the default font style, click “Font.” Choose the font and font size you like, and you’re good to go.
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To change the default font and font size in the Windows version of Outlook, first launch Outlook and select “Options” from the left sidebar. If you don’t see the sidebar, in the upper-left corner of the app, click “File.”

You will see an “Outlook Options” window. In the left sidebar, click “Mail.” In the right pane, select “Stationery and Fonts.”

A “Signatures and Stationery” window will open. Here, in the section for the type of email you want to change the font and font size for, select “Font.”

In the “Font” window, click the “Font” drop-down menu and select a font of your choice. Similarly, select a font size from the “Size” menu.
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Then, at the bottom of the window, click “OK.”.

Select “OK” and “OK” in the other two open windows.
From now on, Outlook will use the font and font size you specified for your emails.
Change the font and font size in Outlook for the web
The web of Outlook also lets you change the font and font size for all your emails or for a specific one.
To change the font and font size for a specific email, open that email. Then, at the bottom of the email body, click the down arrow icon next to the current font name. Choose a new font, and you're done. To choose a font size, click the down arrow icon next to the current size and choose a new size.

If you want to set the default font and font size for your emails, then in the top right corner of Outlook, click the gear icon.

In the open menu, at the bottom, select “View All Outlook Settings.”

In “Settings,” select Mail > Compose and Reply.

In the right pane, scroll down to the “Message Format” section. Then, click the current font name and select a new font. Change the default font size by clicking the current size and selecting a new option.
When you make your changes, at the bottom, click “Save.”

And you're done! Outlook will now format your emails in the font style and font size you selected. Happy emailing!
Information source: howtogeek.com
