Yes it does work with 3rd party add-ons too!

Stremio web > log-in with your account > all your extensions should automagically be installed in your Stremio web. Then open the content you like and share the link in the address bar.

It’s the same on the recipient’s side: They will be able to see the stream you shared, but since they’re guests at first they won’t have any additional add-on installed apart from the opensubtitles add-on that is preinstalled on every account. If you want them to have a specific add-on on top of the stream, they will have to install it on their end first (no account required), then press on your link. Or they can just create an account, install the add-ons once and they’ll always have them ready for when you send them the link. Or you just give them your account and they’ll have all your same add-ons instantly. If you need help troubleshooting something, you can DM me.

P.s. I’m sure you could set-up a native Stremio server, give your friends access through a VPN, share your Plex or other solutions. But you asked for a way to share your Stremio content through a link and this is the fastest way possible.