It is recommended to add a function in the Xodo Android version: save the zoomed PDF.

("It's not that you only zoomed while reading, then closed the file and it reverted back to the unzoomed state."——this is not what I meant. I do not want a temporary(provisional) zoom, I want a forever(lasting) zoom, because a permanent zoom pdf can be printed as a zoomed paper document, but the temporary zoom can not.)

So what I meant is: I zoomed a PDF file, and every pages in it were zoomed -for example,zoom in to 40%- and then I saved the PDF file that has been zoomed (just like the menu "Save a copy" on the upper right which including "Identical copy, Flattened copy, Reduced file size copy, Permanently cropped copy, Password protected copy" so you just need to add a "Zoomed copy" in it.

Then I can copy the pdf of a zoomed copy to somewhere else, like copy and open it on a computer by using whatever a pdf software, the pdf will shows zoomed pages and if I print it, it will become some zoomed papers which including zoomed texts of the pdf of a zoomed copy.

All in all, I want a function that can zoom a pdf and I can save a pdf as a zoomed pdf.