IPv4 is internets protocol address. 4 in IPv mean that it is the 4th version of IP addresses. A great example of what this may look like is that the IP address is written in some type of a dot formatted number called subnet masking. The biggest one known is the normal dot decimal for example, 126.96.36.199. To better understand subnet masking it must be first understood that IP address is in series of four eight-bit numbers which is a 32 bit combined. Subnet mask is a series of numbers followed by 0 for example, 255.255.255.0. These types of addresses have nearly 300 million different combinations of numbers, but are soon to run out. IP addresses are used in nearly everything now in the 20th century. Refrigerators, coffee makers, houses, security, cars, phones, computers, and the list can go on.
When a computer is connected to a LAN network it uses a hardware address and an IP address. This is how one computer recognizes another computer so it may send and receive packets from end to other end. IPv4 consists of 2 identifier parts; Network Identifier and Host Identifier. Network identifier is where your system would specifically be located. Host Identifier is to identify the host of the network. Most networks today use DHCP to configure most IP settings. What DHCP does is it prevents duplication of any given IP address. In some cases an address may be entered in manually.
In today new world there is now an IPv6 version of new IP. With this there will be almost what would feel like an unlimited number of possibilities of IP addresses. The system is very similar but is now with numbers, characters, and symbols. IPv4 will now go down in history and left as nearly a memory as technology advances.