I am new to mikrotik, I want that only one device use on one user id. I give a wan connection to user when he connect on one device with user id, other devices automatically gain internet access by just connected to wifi router. Plz advise about that problem..
Your question is a little bit unclear.
Do you mean that users are sharing their wifi password, and multiple people are connecting using that? Or do you mean that people are connecting routers to your network and then sharing it with their own WiFi from those routers?
There’s not much you can do about the second case - the most you can do is make a mangle rule that sets TTL=1 on all packets leaving your LAN interface and hope the users aren’t smart enough to discover this and set their routers up to reverse the issue…
If it’s the first (users sharing their password) then it depends on whether you’re using hotspot for authentication, or WPA2-Enterprise authentication. Furthermore, are you using RADIUS or local user credentials in the Mikrotik itself?