This will reveal what original font F4 corresponds to. Then match it with your free font.
When software generates a PDF, it assigns generic labels like to the font subsets used in the document. cid font f1 f2 f3 f4 f5 f6 f7 fonts free download work
If you desperately need to print the document but the text displays as gibberish, bypass the font engine entirely. Open the document in your PDF reader. Click . This will reveal what original font F4 corresponds to