If you want to add new custom fonts in your theme then follow below Instruction.

Let’s say you need to add your font.woff file in your theme web/fonts folder, then you need to import that font in Magento, so you need to create new file _typography.less in your theme web/css/source/ folder.
and add your fonts like below

& when (@media-common = true) {
 .lib-font-face(
 @family-name: "Neue Plak W04 Regular",
 @font-path: '@{baseDir}fonts/65781df7-af4a-4a7e-8a89-83876affcd78',
 @font-weight: normal,
 @font-style: normal
 );

 .lib-font-face(
 @family-name: "font-family-name-here",
 @font-path: '@{baseDir}fonts/{your-woff-font-file-name-here}',
 @font-weight: normal,
 @font-style: normal
 );

 
}