How to Change MS Word Default Font

Step1: To change the default font in Microsoft Word, click the dialog box launcher icon in the bottom-right corner of the Font group of the Home tab on the ribbon.


Step2: Here, select the font you want to set as the default, and review the other font settings, such as the style, size, and color.
See the bottom of the dialog box for a preview of how your new settings will look.

Step3: When you’re happy with the changes, click “Set As Default.”

Finally, to ensure the changes apply to all future Word documents,
check “All Documents Based On The Normal Template,” and click “OK.”

Credit : https://www.howtogeek.com/how-to-change-the-default-fonts-in-the-microsoft-365-apps-on-windows/