Hello!
I have been using Okular to insert annotations in PDFs but when I try to view those annotations in an android reader like Librera, I can't see them. Also if I open the pdf in a web browser like firefox they don't appear either.
How can I fix this?

Most browsers won't. That is, they'll probably show color annotations but that's about it. Inserted text annotations and such probably not. As far as pdf goes, browsers are a bit..basic let's say. So, both in chromium based ones and firefox you'd need an extension/addon. Since you mentioned firefox, you could try something like "open in pdf reader", "soda" or "print friendly". The first one: https://addons.mozilla.org/nl/firefox/addon/open-in-pdf-viewer/?utm_source=addons.mozilla.org&utm_medium=referral&utm_content=search.

Thank you for your response!
As I didn't see the annotations on my tablet using an ebook reader like Librera or Redera I looked with firefox and chorme browsers, and they were not visible either.
However annotations made with adobe acrobat I can see them on android.

Why can it be that I can't see them on android either?

Can't help you there. Guess you'll have better luck on some android forum. I checked this and I'm able to see pdf's with annotations sent from pc to phone with connect. I tried the Drive reader and the Onedrive reader. Both do the job.

Can't help you there. Guess you'll have better luck on some android forum. I checked this and I'm able to see pdf's with annotations sent from pc to phone with connect. I tried the Drive reader and the Onedrive reader. Both do the job.

This most definitely is not a problem with Android, but with the way Okular saves those annotations, in contrast to pretty much any PDF viewer found on Windows. It saves them in a way pretty much only Okular and Evince actually display them, while any other PDF viewer saves them in a way every PDF viewer shows them. No extension needed. Also, while this does apply to annotations made with the typewriter input, it doesn't apply to freehand lines.

I have had a similar problem. Okular comments are not visible neither in Master PDF nor Firefox, but they are visible in Okular and muPDF. I worry that comments made with Okular would not be seen by my students that open the PDF files in Windows using Acrobat Reader.

rmorales wrote:I have had a similar problem. Okular comments are not visible neither in Master PDF nor Firefox, but they are visible in Okular and muPDF. I worry that comments made with Okular would not be seen by my students that open the PDF files in Windows using Acrobat Reader.

Depends on how you add them. If you use the comment feature (those yellow sticky notes) they should show up afaik. Also free-hand notes do. But if you use that typewriter feature, those don't show up in every app.

I just did a quick test, inline, pop-up and typewriter show up in Acrobat, in Firefox only pop-up