What can I use to communicate with client to client + client to server?

What can I use to communicate client to client + client to server? I have no idea how to do this and help would be much appreciated

I think you are looking for remote events?

Here is the roblox article about how to use them. (It also has remote functions but that isn’t what you want)

@PoppyandNeivaarecute’s solution is the best, but if they are different players it would be like, does player A send a signal to player B and does player B give a signal to the server? It must go through the server first, instead of:
Client A -> Client B -> Server

should be
Client A -> Server -> Client B -> Server

In the server script you could place a script that saves the entry and the re-entry, I don’t know, it saves a table that contains both players.

Remote events are one way communication from either client to server or server to client. I want something that can send information from the client, to another client. And from the first client, to the server aswell.

Get a local script, add it in starter character scripts or wherever you wanna fire it, fire the remote event, get the server to receive it with all its parameters, and fire another remote event to another client while sending the very same info.

The server can also continue doing its work with the info received from the first client because it has not been lost.