When you download a new typeface from a design marketplace or a free font repository, it almost always arrives as a . While this is great for saving bandwidth and keeping multiple font weights (like bold, italic, and light) together, your operating system cannot "read" or "install" a ZIP archive directly as a font.
Use ZArchiver or the built-in "Files by Google" app to unzip folders and access the TTF files within. Why Use TTF (TrueType Font)? zip to ttf file converter