PDFs aren’t designed to be editor.

The best way to edit is ask your colleague for the word document, edit it and then save as PDF.

Or pay for Adobe Acrobat, make the PDF form fillable and then fill it in anything.

Editor? Nope. Just several different viewers.

Do you know about f-droid? It’s a foss app store for android.

Only thing that I know of which comes close is Librera FD with annotations, otherwise you’ll have to run Linux/Termux + Libreoffice Draw (if that’s even possible)