This would be really useful for me as well. I've been happily using squid for presenting pdf slides in class, but being able to use it for hassle-free pdf annotations would make it even more useful.

As suggested earlier, providing an option in the settings to pick the default behaviour might be the best approach, so that people who prefer editing on copies and keeping the original cash choose to do so, but those of us who want to edit pdfs directly can set the option once and save lots of time afterwards by avoiding the need to manually export all the time (e.g. sometimes I might want to start editing a file on my phone, but then continue on my e-reader)

Yes, this please.
Markup on the PDF is only one step in a longer workflow, where I eventually cut the PDF into pieces for import into an SRS program for future memorization, which happens on the PC.
Having to export each document individually, instead of just being able to overwrite the previous file with one button press (or even automatically) adds a lot of needless busywork and complexity to the process.
I am not the only one with that problem. In this thread someone ended up using the far less functional Xodo and iPad envy, simply because it can be made to directly modify the PDFs without fuss.
Every students may work with hundreds of PDFs these days. It's just such a hassle to deal with the manual export.

https://www.reddit.com/r/GalaxyTab/comments/hshaag/pdf_annotationnotetaking_on_galaxy_tab_s6_upload/

You have to understand, that I'm picking this program up even without this.
But I amost wouldn't have, because "make sure that the program can modify my files without wasted time" is something that might have excluded Squid early on, when I tested pretty much all existing apps for PDF markup/notetaking.
If Squid wasn't so good otherwise, I wouldn't bother.

Many times, as a teacher, I want to be able to import a pdf file from Google Drive and annotate it and then export it back to Google Drive. But I want it to overwrite the original file (replace it). Right now it creates a second file with the same name, but when I am trying to annotate thing to give to student (either through Google Classroom or shared files) I want the option to replace the original.

...and it would be great if this was configurable as the default setting, or achievable in a single click!

2 votes. Reckon this could happen?! :-)

"Save as pdf" button overwriting imported pdf with annotated one.