For annotating PDFs:

• Xournal++
• Rnote

For arranging PDFs:

• PDF Arranger

Okular and Xournal++ both do well for annotating an existing PDF, but you can only add not remove or modify.

For modifying, LibreOffice will do it at the expense of the layout getting seriously mangled even on the simplest of PDFs.

You can do very basic editing in Firefox

Firefox. Firefox can draw, sign, highlight, add text in boxes, add pictures. This should be recommended more.

Libre office Draw also works for basic editing

Libreoffice

Inkscape.

Some people mentioned Inkscape and I can't recommend it enough because it's my goto FOSS PDF editor.

It's not made for PDFs and it shows, bit regardless it's absolutely incredible how versatile it is.

You can keep the formatting, it's vector so no loss of percieved quality, and its Text tool is easy (and fast) to use.

The only problem is each page has to be imported and exported seperstely - you'll have to use something else to combine them

As far as signing goes, if it can be a classic squiggle it's perfect - there's a few pen tools and one has smoothing so you can play with it a bit until the signature looks good.

On mobile, so excuse any typos.

If you have libreOffice installed I believe you can edit pdfs in Draw.

You can also try Inkscape.

I like Okular, but I also use Xournal++.

Another vouch for Xournal++ here. Never in my life have I been so frustrated with software until I was asked to sign a pdf. I also learned this is the entire reason Docusign was created.

Forget editing any wording yourself either unless you want to spend forever fixing the formatting. The ultimate software as a service is paying to edit a fucking document. When I found Xournal it was like finding gold in the ocean as it was seriously the only decent option on Linux.

If you are trying to mark something sensitive out, make sure that you are deleting the actual text or convert the PDF to a flat image after. PDFs can store information in text and images, so if you just draw over some text thinking you are marking it out, there is a chance that the mark out is just a image layer sitting on top of the sensitive text. A way to check this is opening the PDF in Firefox after and toggle Reader View (button in the address bar or F9) to see if you can still see to marked out information.

Several options:

• Master PDF Editor, version 4 is free (and in AUR);
• PDF Arranger, good for bulk edits;
• jPdfTweak, a veritable swiss knife of PDF editing;
• jPDFBookmarks, the best for editing bookmarks;
• Briss, for bulk cutting PDFs;
• Krop, also for cutting, but less flexible.

I have used Krita to edit 1-2 page PDFs, but it's clunky as each page is its own layer. If you're looking for something that lets you add notes to an entire book or something... probably not useful.

I've used Xournal++ before for adding things like signatures to pdfs

If you are into selfhosting then there is a great tool for this called StirlingPDF.

https://stirlingtools.com/

If you asked this on a windows forum years ago, people would say "you can't edfit a pdf by design"

I like how on Linux we have so many solutions and nobody even mentions this

I am going to hop on this post to ask, if anyone has used a linux tablet for school? I am studying and have some regular classes like Math where I want to use a tablrt instead of paper. Some classmates have iPads and while there is some great software available, I would prefer something FOSS. Pine64 have tablets. Did anybode use them for thungs like pdf markups and math equation drawing? As it is my education and I havent been able to find an equivelantly good software I almost want to cave and by a shitpad so I can stop breaking my back with huge books for wich epubs are available.

Scribus works, but it's not terribly user friendly. I've looked around for a while for something that is easy to work with, but haven't found anything better. For some forms, I end up needing to fire up my Windows VM and run Adobe.

Depends what you’re trying to do and what created the pdf. pdftools are good, but they’re command line tools which might not be your scene (dnf/apt/zypper search pdf). Inkscape, Libreoffice are usually a good gui compromise.

In addition to what's already mentioned in the comments, shout out to Inkscape. I guess it's similar to LibreOffice Draw, but I prefer the user experience of Inkscape. Probably more for single-page PDFs.

Overkill for this but just wanted to mention

stirlingtools.com/ (self-hosted PDF magic)

PDF Studio by Qoppa, paid (lifetime subscription) but fantastic, native Linux: https://www.qoppa.com/pdfstudio/

I end up using gimp because I always have it installed and raster is easier than relying on the PDF forms to be set up properly.

If you need something powerful (but maybe not very easy to use at first) GIMP also works great for that.