OAuth stands for Open Authorization protocol.

 This protocol allows you to access the client applications on HTTP for third-party providers GitHub, Facebook, etc. 

It also facilitates us to share resources stored on one site with another site without their credentials.

https://www.varonis.com/blog/what-is-oauth#:~:text=OAuth%20is%20an%20open%2Dstandard,give%20ESPN%20your%20Facebook%20password.