IP stands for Internet Protocol address that functions as a numerical label for each workstation with an Internet connection or that is a part of a local network.
IPs are used for easily identifying the location of any given computer, and consequently allow or restrict access to various services.
Apps that help users hide their IPs replace the real address with a fake one that will make the Mac seem to be located in another country and/or region.
This way, privacy is ensured when surfing the Internet and blocked websites will become accessible.
Some of the apps that allow IP hiding will also offer their users the option to choose the new IP, and most of them will automatically replace the address with another one if necessary.