Teleporting player to another server?

So currently I’m sitting building a plugin but the thing is i want to use Velocity but dont know how i can send a player to another server if clicked on item so that why I’m coming here.

So how do you exactly do that ?

Be in mind its a server plugin no a proxy plugin.

Install BungeeQuack on the proxy then follow the tutorial for Bungeecord, or just use a plugin compatible with Bungee