[Discussion] Can i do client stuff in a server sided plugin?

Hey everyone,
I’m new to scripting in lua and new to script fivem servers[Started around 2days ago]
I’m interested if everything what the player can see or do is client-sided?
Whether it’s done directly or indirectly, it’s client-sided right?

As an example, I’m working on a chat plugin, where i wanna make a command where the player can write something which can be seen by everyone, like:
[ADMIN ANNOUNCEMENT] The Event Starts In 5Minutes

I must make a client-sided part with an msg command and a player loop in the server-sided part to make it visible for everyone, right?

Edit: - Spelling