is it possible to make a name tag gui for all players?

script:

local billboardgui = game:GetService("ServerStorage"):WaitForChild("BillboardGui")
game.Players.PlayerAdded:Connect(function(player)
	local clonedgui = billboardgui:Clone()
	clonedgui.Parent = ?
end)

? = what is the parent can i use local player?

You need to use the CharacterAdded event.

local billboardgui = game:GetService("ServerStorage"):WaitForChild("BillboardGui")
game.Players.PlayerAdded:Connect(function(player)
	local clonedgui = billboardgui:Clone()
	player.CharacterAdded:Connect(function(char)
		clonedgui.Parent = char.Head
	end)
end)