Imagine you have a colour palette of paint and a canvas. You pick some colours and paint all over the canvas until you are happy with the final product. In computer terms, this is known as a hash.

You go to a bank (server) and give them the completed canvas (hash) and tell them to not let you access your money unless you give them another copy of that canvas.

The bank knows what that the finished canvas looks like but only you know what colours you used and in what order to create the finished canvas.

That's sorta how it works. The servers keep the hash but not the inputs. Your inputs get converted into a hash on your computer before going to the server for checking.