Method

Place the font file in the public or assets folder.

Edit .vitepress/theme/style.css and add the following at the end:

@font-face {
  font-family: 'FontName';
  src: url('PathToFontFile') format('truetype');
}

:root {
--vp-font-family-base: "FontName";/* Other text font */
--vp-font-family-mono: "FontName";/* Code block font */
}