Your own IP address uniquely addresses the device with which you are connected to the Internet. It can thus be understood as a kind of unique address of the device. Using the IP address, it is possible that data can be transported from a sender to the intended recipient. Once you connect to the Internet, e. g. via a DSL router, your Internet provider assigns you an individual IP address.
There are two standards for defining IP addresses. The newest one is IPv6, which provides a very long address for addressing an almost infinite number of devices. An IPv6 address, for example, looks like this: 2001:db8:0:8d3:0:8a2e:70:7344. The second and obsolete standard is IPv4, which is gradually being replaced by IPv6 because it provides only a very limited number of possible IP addresses. A typical IPv4 address looks like this: 126.96.36.199.
Knowing the own IP address can be useful if you want to share it with others. To find out your own IP address, you can use an online tool like the one offered on this page. A big advantage of online tools is that you can see your own IP address in a way that is visible to other Internet users. Other Internet users are e. g. servers that can be accessed with your own device. Geo-IP tools also make it possible to find out the approximate location of the connected device for your own IP address or a foreign IP address.
However, the IP address can also be retrieved on your own device without using online tools. There are certain utilities in the operating system you are using, e. g. in the "Network" area of the system settings. However, what has to be considered here is that if you are in a local network (LAN), you will mainly see the so-called internal IP address of your device. That is the IP address which is used between your own device and a switching device, such as a router, to access the Internet. An internal IP address has normally the format 192.168.x.x.
By the way, many people simply say "my IP" in shortening instead of "my IP address". Since the acronym "IP" stands for "Internet Protocol", this abbreviation is wrong. In other words, is not your own Internet protocol when you talk about the Internet address of your own device. Whoever wants to find out his own IP usually wants to find out his own IP address.