How can i allow specific people to view a screen gui?

So basically, I want to make it so only me and my friend have access to a ScreenGui. any help?

Put your screen Gui in ReplicatedStorage and put the script in ServerScriptService.

local players = {"sgtbermido1"} --Change the names to whoever you're giving the gui to
local gui = game.ReplicatedStorage.ScreenGui --Change ExampleGui to the Name of the Gui you're giving to the allowed players

game.Players.PlayerAdded:connect(function(plr)
	plr.CharacterAdded:connect(function(chr)
		for i = 1, #players do
			if players[i] == plr.Name then
				gui:Clone().Parent = plr:WaitForChild("PlayerGui") 
			end
		end
	end)
end)

or

put this inside of your button

if game.Players.LocalPlayer.Name == "jackwater0" and "jackwater600" then ---- Change "YourNameHere" to your Roblox Username and "FriendsNameHere" to your friend's username
	script.Parent.Visible = true
else
	script.Parent.Visible = false
end

make sure you uncheck the Visible of the button in properties

Here is a quick script that you can add and play around with:

local player = script.Parent.Parent.Parent
local gui = script.Parent

if player.Name == "YourNameHere" or player.Name == "YourFriendsNameHere" then
	script.Parent.Frame.Visible = true
elseif player.Name ~= "YourNameHere" or player.Name == "YourFriendsNameHere" then
	script.Parent.Frame.Visible = false
end

You can maybe make a group (Or use a group that you own already) and make a rank for you and your friend and use this script to allow only the two.

local players = game:GetService("Players")
local player = players.LocalPlayer

local GuiFrame = script.Parent -- Change "GuiFrame" to the name of your ScreenGui.Frame

if player:GetRankInGroup(10490042) >= 254 then -- Change "GroupID" and insert your Group ID, and also change "254" to the number of your friend's rank (It should be the 2nd most powerful role in the group, you may decide to change it or not.)
	GuiFrame.Visible = true -- Change "GuiFrame" to the name of your ScreenGui.Frame
else
	GuiFrame.Visible = false-- Change "GuiFrame" to the name of your ScreenGui.Frame
end

This should work, as I've tested it. Let me know!