Move your desired font files to ux0:data/font/ (you may need to create this folder).
For those using their Vita primarily for emulation via RetroArch, using a classic Nintendo or Sega-style font package can help unify the retro gaming experience. How to Install Custom Font Packages ps vita firmware font package best
To install these, you will primarily use the homebrew application by vitasdk or GrapheneCt . Move your desired font files to ux0:data/font/ (you