How to photograph documents without shadows
The most common flaw in document photos is not blur or tilt — it is your own shadow, cast by you and your phone standing between the light and the page. A few small changes to how you shoot remove most shadows at the source, and document-mode enhancement can clean up much of the rest.
Where shadows come from
A single overhead light behind you is the classic setup for a phone-shaped shadow across the page. Turn the document (or yourself) so the main light comes from the side, and the shadow falls off the page instead of across it. Near a window, put the page so the window light rakes across it sideways.
Five quick fixes
Shoot from slightly off to the side and let perspective correction straighten the angle later. Use two light sources if you can — a room light plus a desk lamp cancels most hard shadows. Move away from walls, which block half the ambient light. Avoid flash directly above glossy paper; it trades a shadow for a glare spot. And when the light is hopeless, a slightly angled shot with even lighting beats a straight-down shot with a stripe of shadow.
What software can rescue
Soft, gradual shading is exactly what Document mode removes: it estimates the background illumination and evens it out, so a lightly shaded page comes out uniformly white. Hard-edged dark shadows are harder — the pixels under them lose contrast that no filter can fully restore. Fix hard shadows at shooting time; let the software handle the soft ones.