127.0.0.1 is a special IP address that loops back to the device itself.

For local area networks there are 3 groups of private IPv4 address spaces

192.168.0.0 - 192.168.255.255 172.16.0.0 - 172.31.255.255 10.0.0.0 - 10.255.255.255

Basically you can use any address range in any of those 3 ranges, ones in the 192.168.x.y block have been pretty common for home routers for a while.

Normally you can change the address ranges set in the router if there’s a particular range you want to use.