DHCP (Dynamic Host Configuration Protocol) is a network protocol used to automatically assign IP addresses to devices on a network. DHCP is typically used when connecting new devices to a network or when changing the IP address of an existing device.
When a device is connected to a network, it will send out a DHCP request in order to obtain an IP address. The DHCP server on the network will then respond with an IP address that the device can use.
DHCP can also be used to provide other information to devices on a network such as the DNS server address or the default gateway address.