PDF files are really useful for moving documents around when you ‘need’ the recipient to be able to open in a pdf reader and see what you intended.
Unless you have access to expensive software you are usually not able to edit these files easily. While LibreOffice draw can perhaps do this, it may not be ideal for the job.
Xournal  is a Debian application, that while mostly aimed at touch screens, is able to annotate pdf files as the video below demonstrates.
As mentioned in the video notes, Xournal will export as a **.pdf.pdf file**, so you may want to rename it when saving. This is not even an issue for me.
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Originally published 10/1/2020 on Author’s personal blog. Reproduced here by original author.
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