How to add fonts to macOS Catalina

 

How to install fonts on macOS Catalina from a folder

  1. Locate the font you wish to install
  2. Right click (trackpad: ctrl+click or two-finger tap) on the font file
  3. Select Open With
  4. Select Font Book
  5. Select Install Font

Source: How to add fonts to macOS Catalina | Appleinsider