Every IP address belongs to a network, and every network has a number. Looking up an address returns that number and the owner's name. This is how a website tells a home connection from a server: the owner is either a consumer internet provider, a phone carrier or a hosting company.
The three kinds of proxy differ in exactly this. A residential proxy exits from a home provider's network, a mobile proxy from a carrier's, a datacenter proxy from a host's. Bot filters weigh the network heavily when deciding whether to trust a visitor.
Read next: Residential vs datacenter vs mobile proxies