New today the ability to edit an Image, resize, add colored lines and Add a Header, Footer with page numbers.
Video does not show resizing, that's easy just pinch zoom in Print Layout, remember Print Layout ..
Add a header or footer
1, Open a document in the Google Docs app.
2, Tap Edit Edit.
3, In the top right, tap More More.
4, Turn on "Print Layout."
5, Tap the header or footer.
6, Type the text you want in your header or footer.