Are you trying to take a photo of a small document or a document that is not rectangular?
For small documents, zoom in on the mobile device screen using two fingers before taking a photo.
A photo of a document that is not rectangular cannot be taken automatically. After taking a photo in manual photo-taking mode, tap the thumbnail displayed at the bottom of the mobile device screen to open the Preview screen, and then tap to adjust the crop area.
Is the document folded, curled, or tilted?
Flatten the document and place it straight before taking a photo.
Is the color of the document you are taking a photo of similar to the color of the surface on which the document is placed? Also, does the surface have a pattern?
Place the document on a plain surface that is a different color from the document, with no lines, text, or other patterns, and then take a photo of it.
Does your mobile device camera have a resolution of 12 MP or higher?
If your mobile device camera has a resolution of less than 12 MP, a photo may not be taken automatically.
After taking a photo in manual photo-taking mode, tap the thumbnail displayed at the bottom of the mobile device screen to open the Preview screen, and then tap to adjust the crop area.
For details about how to check the camera resolution, refer to the manual of your mobile device.