Document Customizer comes with three fonts as a standard. But it is possible to use all fonts preinstalled in Business Central.
You can see here which fonts that are supported
Add supported fonts to Document Customizer
To add a new font, go to Layouts and click on the Look up field on Font, and Add new.
Write the name on the font, it must be spelled as in the list on Microsoft page.
Click on OK and the font has been added and will be use.
Please be aware that when changing fonts and font size, columns size might not be of optimal dimensions. Please have this in mind when changing font especially.