FYI LibreOffice Draw allows you to open, edit and digitally sign PDF files
I see the question asked a lot in Linux groups, so I hope this bit of knowledge may help someone here.
Thank you, that's an important distinction to make.
A digitized handwritten signature is not a digital signature. The latter is valid and enforced in court in some countries, the former is worthless.
I've found Xournal++ is good for markup as well
File > Digital Signatures > Sign Existing PDF...
I'm currently using LibreOffice 7.3.
Good to know that you can digitally sign PDFs in LO Draw, thanks!
Inkscape is decent for basic PDF editing as well, though depending on the font the textboxes can end up mangled when you edit them. The import is supposed to me even better in version 1.3, but I haven't had a chance to try it
Just use GIMP. It can do multiple pages of pdf too.
But can it edit text fields ? like not drawing over them but changing the actual text stored
How good is it? Say I have a textbook and the errata, can I manually copy the updates from the eratta to the textbook without loosing the chapter markers?
PDF editing is never pretty.
The format itself was intended for finished document, not for editing. The editing you can do very much depends on the application that created the document, but most documents I see are just a bunch of unconnected textboxes and images, so not very edit-friendly. Some PDF files, scanned in documents for instance, are just bitmap images strung together.
You can do basic editing, but how easy it will be depends on how the document was created.
TLDR: if you need to do a quick fix, LibreOffice Draw will help you. If you need to do a lot of editing, you'll have to pay Adobe for the privilege.
LO Draw has trouble with editing if PDF has fonts that aren't installed system wide. They are auto-replaced with another font and texts with unknown fonts may move slightly compared to original document.