FileHero guide
Change PDF fonts and preserve heading sizes with AI
Change PDF font family, body size and emphasis with an AI proposal, while keeping headings distinct and checking text fit.
Be specific about the scope
Try: “Change the body font to Times New Roman, 12 points. Keep heading sizes unchanged.” Name a page or phrase if only one section should change.
Why exact sizes may not fit
PDF boxes are fixed in position. A wider font or larger size can run into nearby content. If you request an exact size that cannot fit, the edit may be rejected rather than silently reduced. Try a narrower request, a smaller size, or move the text to leave more room.
Check headings and small print
Heading detection uses typography and is not perfect. Inspect short bold labels, tables and footnotes with See changes. Undo and narrow the request if a label was treated as a heading incorrectly.
Download a checked copy
Existing-text formatting requires Premium to download. Keep the source and open the exported PDF to verify appearance in another viewer.