A VPN is just a app that makes it so it looks like your in another part of the world but in the comfort of your home
A VPN can also give you access so YouTube videos that are not available in your country and access websites (sometimes even websites restricted by your school, work, etc.)
You can also use it to protect your privacy, etc.
Theirs a lor of VPN that are free and some are paid (just write vpn in the playstore)
Videos might be a little slower to load as a FYI but it depends on the app, which servers you picked etc.
This is one of them just click the carrot icon
https://play.google.com/store/apps/details?id=free.vpn.unblock.proxy.turbovpn