This is the most reliable method if you plan to share the PDF or send it to a professional printer. You will need to re-create the PDF correctly.
: Open the PDF in Acrobat and go to File > Properties > Fonts . It might list the "Actual Font" (like Arial or Calibri) that the CID names are masking. You can then download that standard font instead. cid font f1 f2 f3 f4 free download free
: Your computer looks for a font actually named "CIDFont+F1" and can't find it because it doesn't exist in the real world. This is the most reliable method if you
Searching for "CID font F1 F2 F3 F4 free download" is usually a wild goose chase. "F1" is likely just a placeholder name inside a specific PDF. Downloading random files to match this criteria exposes you to malware and copyright infringement. It might list the "Actual Font" (like Arial