We do allow some custom fonts/typefaces on Fandom, but please make sure that text remains readable - accessibility is very important. Please make sure to check out https://community.fandom.com/wiki/Customization_policy before proceeding!
We first recommend you check out the built-in heading font options in ThemeDesigner, as they may suit your needs.
If you wish to go beyond that, this is an option that doesn't require uploading font files: https://community.fandom.com/wiki/Help:How_to_import_Google_Fonts
If that does not help, let us know which specific font types you need to use (we allow WOFF2, WOFF, OTF, and TTF), and we can look into enabling them. Note: please make sure the font is appropriately licensed for this kind of usage.
We cannot provide significant assistance with applying the font to text on your wiki - but you'll likely want to make use of custom community CSS to do so: https://community.fandom.com/wiki/Help:Community_CSS_and_JS
(https://custom.fandom.com/wiki/Custom_fonts may help, but note that it is not an official help page.)