The (IP ) which is term as Internet Protocol,

Function: to identify the host on the internet

Why the subnet is there to identify which type of network the host is connected to to access the internet

And than we also have Default Gateway:

Function;

It to identify what networking device the host is connected to to access the internet.

These are the 3 IP address configuration that needs to be correct before the host can be able to send and receive information on the internet

IP address
Subnet mask and
Default Gateway