DHCP (Dynamic Host Configuration Protocol) is a network service that automatically hands out IP addresses and other connection settings to devices when they join a network. Without it, you'd have to manually type in an IP address for every phone, laptop, and printer.
When you connect to a Wi-Fi network or plug in an Ethernet cable, your device sends a request to the DHCP server (usually your router). The server leases an available IP address to that device for a set period, typically a few hours or days. Once the lease expires, the device can renew it or be assigned a new address. This prevents address conflicts and keeps your network running smoothly.
A real-world example: you bring a new tablet home and connect it to your Wi-Fi. Your router's DHCP server automatically assigns it an IP address like 192.168.1.105. Your tablet can now communicate with other devices and access the internet without any manual setup. When you take it elsewhere and connect to a different network, that router's DHCP server assigns it a different address suited to that network.
When buying a router or network equipment, DHCP support is standard on virtually all consumer devices. However, if you're setting up a small office or advanced home network, you may want to check that the router allows you to configure DHCP settings, such as the range of IP addresses it can distribute or how long leases last. Some people also disable DHCP on certain devices that need a fixed IP address, such as a network printer or security camera, and assign a static address instead.
For most home users, DHCP is invisible and automatic. It's one of the reasons modern networks are so easy to use: your devices simply connect and work.