The PDF relies on the user's computer to have the font installed. If the viewer lacks that specific typeface, the system tries to substitute it.

When a PDF displays text incorrectly and lists a "CID Font F1" error, it is generally caused by one of three issues:

CID (Character ID) is a font format developed by Adobe, primarily designed to support large character sets for East Asian languages like Chinese, Japanese, and Korean. These fonts can contain thousands of glyphs.