Hi, please see if any of these work for you -

https://addons.mozilla.org/en-US/firefox/addon/save-as-pdf/

https://addons.mozilla.org/en-US/firefox/addon/print-to-pdf-document/

https://addons.mozilla.org/en-US/firefox/addon/online-pdf-editor-pdf2go-com/

If your question is resolved by this or another answer, please help other users by marking the best reply as Solved. Thank you!

The concern I have with your links is that all of the add-ons suggested have not be vetted and are not recommended.

Recommended extensions have undergone a deeper examination and they have a lot of users. Not all useful extensions can be examined, so whether an extension is recommended or not shouldn't be a reason not to try out an extension.

You can check the reviews of an extension to see how they are rated and if there are issues reported.