Share a link
Pick the meeting application — the page works the rest out on the other machine. You do not need to know which macOS they are running.
The link
https://gizmoparty.com/mac-sharing-tutorial/en/zoom/detect/#fernsteuerung
A message ready to paste
QR code
Only useful when you are in the same room and can show the code on a screen. In a video call the link belongs in the chat — the recipient needs it on the Mac, not on their phone.