Dear sir,
I have a laptop with inbuilt Wi-Fi router. My friend also has a laptop of the same type. Now I want to connect my laptop to my friend's laptop in LAN using Wi-Fi . Is it possible to have a video call without connecting to internet.
Reply me please

Can you both connect to the same LAN (Local Area Network)? If so, you can easily connect without connecting to the Internet.

A LAN is a local network. There may, or may not be a connection from the LAN to the Internet, but computers typically receive IP addresses from the LAN and can communicate with each other.

You say your laptop has a "built-in Wi-Fi router". Are you sure or is it simply a Wi-Fi adapter card? The "router" indicates that it can provide IP addresses and other computers can connect directly to it. Please explain exactly what your computers have.