Sometimes, the font is installed on your system, but the PDF viewer’s font cache is corrupted. The program scans for the font, fails to locate it correctly, and defaults to substitution.
Before saving as a PDF, go to Options > Save > Embed fonts in the file. Download Font Substitution Will Occur
However, the visual result can range from nearly identical to completely illegible. Sometimes, the font is installed on your system,
The document may be using a font format (e.g., old Type 1 PostScript fonts) that is not supported by newer operating systems or software, forcing a change to a more modern format like OpenType or TrueType. The Impact of Font Substitution fails to locate it correctly