Open Edit PDF text and choose your PDF. The editor opens with big coloured buttons at the top: Edit text, Add text, Picture, Sign, Highlight, Erase, Draw, Shapes, More.
Tap Edit text, then tap the line you want to change. A box appears around it.
Type your change. Urdu and English both work. When finished tap Done; the panel closes so the whole page stays visible.
Changed your mind? Tap Restore original in the panel, or tap the ↶ Undo button at the top.
When finished, tap ⬇ Download at the top to save the edited PDF.