If you are trying to view a legitimate CJK (Chinese/Japanese/Korean) document and are getting substitution errors, you likely need the standard Adobe CIDFonts. Adobe provides these for free to ensure PDF compatibility.
Understanding CIDFont F1, F2, F3, and F4: Causes and Solutions cidfont f1 f2 f3 f4 gratis
If you open a PDF with missing fonts, many viewers substitute incorrectly. For professional work (editing, re-printing, preflight), you need the . Fortunately, in many cases, F1–F4 map to four standard, freely distributable PostScript fonts : If you are trying to view a legitimate
Be cautious of websites claiming to offer a "CIDFont F1" download link. Since these are usually internal software identifiers rather than standalone typeface files, these sites may be untrustworthy or providing generic substitutes. CID+ Fonts - Adobe Community you need the . Fortunately