A PDF can use embedded font data or rely on substitution when a font is unavailable. Adobe explains that embedding depends on the font's permissions. If letter shapes change on another computer, font handling is a useful lead, not the only possible cause.
Compare the exact file
Suppose a one-page invitation looks right on your laptop but its heading looks strange on a friend's screen. First confirm that both of you opened the same exported PDF, not the editable original or an earlier attachment. Give the new export a distinct filename.
In Acrobat, inspect the document's font information. Record the font names and whether embedding is reported. If you control the source document, review the export settings and the chosen font's permitted use. A replacement font may be simpler than trying to force a restricted one into the file.
Recheck the whole page
- Compare the heading, small text and unusual characters.
- Check page count and important line breaks.
- Open the exported copy in another viewer.
- If printing matters, inspect a sample before ordering many copies.
Do not turn every page into a screenshot as an automatic fix. That changes how the document can be searched and read. Keep the editable source, solve the specific font problem and verify the new PDF rather than assuming that a successful export guarantees the result.