How to send messages to the chat with a script?

So I know some games, make stuff say in the chat when you join, I'm pretty sure they don't use a custom chat. How did they do that? Or is it just a custom chat? I searched on the wiki, on YouTube, even looked for a question asked about it, but I couldn't find anything.

If you want the server to "Chat" when the player joins and the player leaves, you would need to put this into a LocalScript inside StarterPlayerScript:

See comments in the code to get a better insight of how this script works!

If there are any typos, then please excuse me, I wrote this code here and now.

pcall(function() --Event that should fire when the player joins
	game.StarterGui:SetCore("ChatMakeSystemMessage", {
		Text = "[Server]: " ..game.Players.LocalPlayer.Name.. " has joined the game!";
		Color = Color3.new(255, 255, 255); --The color of the text
		Font = Enum.Font.SourceSansBold; --The font of the text
		FontSize = Enum.FontSize.Size24; --The size of the text
	})
end)

game.Players.ChildAdded:connect(function(player) --Event that fires when player joined
	if not pcall(function() --If the pcall() function was not called
		game.StarterGui:SetCore("ChatMakeSystemMessage", { --Gets the chat
			Text = "[Server]:  " ..player.Name .. " has joined the game!"); --Sets the text
			Color = Color3.new(255,255,255); --Sets the color of the text
			Font = Enum.Font.SourceSansBold; --Sets the font of the text
			FontSize = Enum.FontZise.Size24; --Sets the size of the text
		})
	end)	  then
		print("Error") --prints error if the pcall() function was not called
	end
end)

game.Players.ChildRemoved:connect(function(player) --Event that fires when player left
	if not pcall(function() --if the pcall() function was NOT called
		game.StarterGui:SetCore("ChatMakeSystemMessage", { --Gets the chat
			Text = "[Server]:  " ..player.Name .. " has left the game!"); --Sets the text
			Color = Color3.new(255,255,255); --Sets the color of the text
			Font = Enum.Font.SourceSansBold; --Sets the font of the text
			FontSize = Enum.FontZise.Size24; --Sets the size of the text
		})
	end)	  then
		print("Error") --prints error if the pcall() function was not called
	end
end)

For more information, visit this link: http://wiki.roblox.com/index.php?title=API:Class/StarterGui/SetCore

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