Is there a free pdf editor that can modify a pdf file

[GregD001]

Is there a free pdf editor that can modify a pdf file.
I really just would like to add highlights to a pdf document. and have them stay in the pdf file.

[SuaSwe]

I've never used it myself but it looks like Okular may do what you want. It's available via Ubuntu's Synaptic package manager and will highlight PDF docs as you specify.

[amauk]

Both Libreoffice and Gimp can open PDFs

[cotcot]

Have a look at PDFedit.

[SuaSwe]

Can they edit them though, amauk? I didn't think you could make any alterations such as highlighting in LibreOffice, and I believe GIMP requires an add-on for it (which would be an alternative to installing a new app, should the OP wish) - I could be wrong though!

[frncz]

Editing existing text is difficult, but filling in boxes etc can be done with xournal. Quite a clever program.

[ajgreeny]

LO can edit PDFs, though very often the formatting of originals is very garbled and makes them pretty useless, in my opinion.

I have not tried pdfedit for some time now, but I did not have any great success with that either; perhaps I did not try hard enough, or perhaps the pdf files I tried it on were simply images, as many are.

Not sure about GIMP, which will certainly open PDFs, but if an add-on allows it to edit them, it is certainly worth investigating.

[sudodus]

Editing existing text is difficult, but filling in boxes etc can be done with xournal. Quite a clever program.

+1
I use xournal to high-light or make notes on pdf files.

from man xournal

DESCRIPTION
       This manual page briefly documents the xournal command.

       Xournal  is  a GTK+ application for notetaking, sketching and keeping a
       journal using a stylus. It can also be used to add annotations  to  PDF
       files and graphics files.  It takes no options.

It can write to its own file format (which can be edited again), or export to a pdf file.

[cortman]

+1
I use xournal to high-light or make notes on pdf files.

from man xournal

DESCRIPTION
       This manual page briefly documents the xournal command.

       Xournal  is  a GTK+ application for notetaking, sketching and keeping a
       journal using a stylus. It can also be used to add annotations  to  PDF
       files and graphics files.  It takes no options.

It can write to its own file format (which can be edited again), or export to a pdf file.

Tried Xournal- saves the edits as a new xournal file? Fail.

I downloaded and installed PDF XChange Viewer through Wine, and never looked back. Best PDF viewer/highlighter/comment program I ever saw or used, and works perfect through Wine.

[crazyness003]

Tried Xournal- saves the edits as a new xournal file? Fail.

I downloaded and installed PDF XChange Viewer through Wine, and never looked back. Best PDF viewer/highlighter/comment program I ever saw or used, and works perfect through Wine.

On the contrary, you can save as a new xournal file (.xoj) OR you can Export as PDF
File -> Export to PDF

In my opinion, PDFedit is very, very frustrating. It's slow, clunky and almost unusable. There is a lot of back-end stuff I can apparently do, but for a quick PDF edit, Xournal has become my champion.

Of course, there are some formatting issues that may be considered extremely annoying, but as far as I know, every PDF editor does that. It all has to do with encoding.