What should I request to server?

I started programming with Godot. One of my games I want to make it Multiplayer. One of the first questions after starting programming is what should send the Client to the Server to Synchronize. The game is a 3D game that need to interact with collisions and the physics of each player does.
For example, I should only send to the server that I shot a bullet and then the two players process this shot or the server needs to process the destruction and then send the result of it to the clients?

If someone knows exactly the best practices to Server-Client connections I will be so greatefull!
Thank you.

Usually clients would only send inputs, while the server would process those inputs however you want it to.

For example, the client could say, I change direction, I move left, I shoot, etc., then wait till the server acknowledges that input saying it’s valid.

Check out this GDC talk, https://youtu.be/W3aieHjyNvw starting at 22:30