Question

A device that forwards packets between networks by processing the routing information

Answer 1

This is called routing, and though it gets very complicated in the details, the basic idea is (fairly) straightforward. For simplicity let’s consider only IPv4, which is still the most used protocol. IPv6 is slightly different in detail but not that much in principle. The 32 bits of an IPv4 address are split into two parts. The leftmost n bits define the network, and the rest define the node within that network. The size of n depends on various traditional rules but nowadays mostly uses something called CIDR

Answer 2

Router is the device which is used for routing