Ara said

I cannot copy and paste between firefox/emails and word files anymore. I can't copy and paste a link to put in an email either.

Nothing has changed with Copy & Paste. Is your Firefox up to date to the latest version? What version of Word are you using?

Everything is up to date to the day, word and firefox. Word for mac 16.30. Today's Firefox update. I do all updates. I am still on Mojave - pre-Catalina as I can't get into Catalina right now - but this has been going on for a long while, through various updates of firefox and word, and etc. It started after a firefox update a long while ago. But it is really getting in the way of my work. Copy and paste work fine IN word but never anymore between apps.

This seems more likely a device problem, not specifically Firefox. Have you tested copying from a different web browser?

seems like I can grab a bit off text off safari and drag it to my desktop (like I used to be able to on firefox,) but nothing else works.

Try using this Add-on using the link below.

https://addons.mozilla.org/en-US/firefox/addon/absolute-enable-right-click/

Lots of questions but NO answers, use now Opera for my web page as Firefox fails, for the rest I use Firefox.

Did you try to reboot the computer ?