IPaddress is how a particular node on the Internet is identified.
Some IPs are statically assigned (businesses) while others are dynamnically assigned.
Every transaction on the Internet is identified by its IPaddress. These transactions are logged and archived by the major Internet service providers (ISPs).
Access to the Internet is provided by an ISP to a client to whom they assign an IPaddress.
The client identification information is stored in the ISP's database and is connected to their assigned IPaddress.
It is possible for an ISP to turn off service to an individual client or multiple clients at will.