How To Create an Open/Close GUI?

The active user-interface doesn't reside under StarterGui. This Service acts as a container for the general UI assets that are to be replicated to each individual Client (Player). For an easier explanation, It is akin to the way StarterGear behaves.

In order to individually modify local GUIs, you must reference the PlayerGui container, within the LocalPlayer.

--###----------[[SERVICES]]----------###--
local Players = game:GetService("Players")



--###----------[[VARIABLES]]----------###--
local Player = Players.LocalPlayer


local PlayerGUI = Player:WaitForChild("PlayerGui")

local GamepassesGUI = PlayerGUI:WaitForChild("Gamepasses")

local ShopFrame = GamepassesGUI:WaitForChild("Shop")

local ButtonContainer = GamepassesGUI:WaitForChild("FrameA")
local OpenButton = ButtonContainer:WaitForChild("ImageButton")



--###----------[[FUNCTIONS]]----------###--
local function OnButtonClicked()
    ShopFrame.Visible = (not ShopFrame.Visible)
    --// Simplifies your conditional scope.
end



--###----------[[SETUP]]----------###--
OpenButton.MouseButton1Click:Connect(OnButtonClicked)

Using not is better in this scenario, it reduces the amount of time it takes to write it.

local Players = game:GetService("Players")

local LocalPlayer = Players.LocalPlayer
local PlayerGui = LocalPlayer:FindFirstChildWhichIsA("PlayerGui") -- PlayerGui, not StarterGui

local Gamepasses = PlayerGui:WaitForChild("Gamepasses")
local FrameA = Gamepasses:WaitForChild("FrameA")
local ImageButton = FrameA:WaitForChild("ImageButton")

ImageButton.MouseButton1Click:Connect(function()
    Gamepasses.Shop.Visible = not Gamepasses.Shop.Visible
end)

heres how starter gui works, whatever you put inside of the starter gui will be inside of the client, becuase of that, it is no longer inside of the folder "StarterGui." Instead, it is inside of the folder inside of the "Players" service. The Folder is called "PlayerGui." Anyways, if you put a script inside of the button, it will also get copied into the "PlayerGui" Folder

example of "PlayerGui" :

https://drive.google.com/file/d/1sFoO6r4G_i_wjQALyQi3f1FUQAbaxY8K/view?usp=sharing

what your ui should look like:

https://drive.google.com/file/d/1ejqMceShvdoZ0O0n9uQ1GSW1ypOTyne8/view?usp=sharing

(paste the link into your browser)

put the script inside of the button

local button = script.Parent
local frame = script.Parent.Parent.Frame
button.MouseButton1Click:Connect(function()
    if frame.Visible == false then
        frame.Visible = true
    else
        frame.Visible = false
    end
end)