Font file formats
6 formats in this category.
Font formats store the shapes of letters as outlines, plus hinting and metadata. Web fonts are compressed for fast download, desktop fonts favour broad app support.
Desktop and web font formats
Font formats store letter shapes as outlines plus hinting and metadata. TrueType (TTF) and OpenType (OTF) are the desktop standards; OpenType is a superset that adds advanced typographic features and can carry either TrueType or PostScript outlines. For the web, WOFF and WOFF2 wrap those same outlines with compression for fast download, and WOFF2 (Brotli-compressed) is now the default web font format because it is the smallest.
A TrueType Collection (TTC) packs several related fonts into one file to save space when a family shares glyphs, common for the large fonts that ship with operating systems.
Installing versus embedding
Desktop fonts (TTF, OTF) are installed into the operating system so every application can use them. Web fonts (WOFF2) are not installed; they are downloaded by the browser and used only on the page that requests them via CSS. Using a desktop font on a website, or a web font on the desktop, usually means converting between the two.