If you are getting an error saying the font is missing, the best solution is usually substitution. Since CID F1 is often a generic placeholder:

Many users find that replacing the missing F1 font with common families like Arial , Roboto , or Times New Roman restores the intended look.

Older PDF creators used naming conventions that modern viewers sometimes struggle to interpret. How to Fix CID Font F1 Issues (Without a Download)

This is a sample text in CID Font F1 Normal. The font is clear and readable, making it easy to read.