How do you show and hide gui when clicking a part?

You might want to use PlayerGui, so it only works for the player who clicked it.

To get the player, we can use a player added event.

Script:

game.Players.PlayerAdded:Connect(
    function(player)
        print(player.Name)
    end
)

Now, once we've done that, we'll have to detect if the player clicks the part.

game.Players.PlayerAdded:Connect(
    function(player)
        print(player.Name)
        local ClickDetector = workspace.Volcano.Keypad.ClickDetector

        function onMouseClick()
            print("Clicked)")
        end
        ClickDetector.MouseClick:Connect(onMouseClick)
    end
)

After that, we'll have to make it toggle enabled. To do this, we'll just have to do an if statement detecting if it's enabled or not.

game.Players.PlayerAdded:Connect(
    function(player)
        print(player.Name)
        local ClickDetector = workspace.Volcano.Keypad.ClickDetector

        function onMouseClick()
            print("Clicked)")
            if player.PlayerGui.Keypad.Enabled == false then
                player.PlayerGui.Keypad.Enabled = true
            else
                player.PlayerGui.Keypad.Enabled = false
            end
        end
        ClickDetector.MouseClick:Connect(onMouseClick)
    end
)

Accept the answer if it worked.