How do i make a text when i chat something?

Ok, so it seems like you want it to get what the player says after the /me.

To do this you can do something like:

game.Players.PlayerAdded:Connect(function(Player)
    Player.Chatted:Connect(function(ChatText)
            print(Player.Name, " has chatted")
        if  string.sub(ChatText,1,3):lower() == "/me" then     --Checking if the player says "/me", I am lowering it because they player might do the m uppercase or e uppercase
            local afterText = string.sub(ChatText,  4) --When using string.sub(), first argument is the string and the second is from where it shall begin, third (optional) is deciding if you want to check from 1 to 2
            print(afterText)
        end
    end)
end) 

game.Players.PlayerAdded:connect(function(player)
    player.Chatted:connect(function(msg)
       if msg == "/me" then
    -- need help here
end