Player Gui Appear On Touched, Wont Work?

You can’t get the local player on a server script. A server script is just a regular script. You can get the player within the touched event by calling a function :GetPlayerFromCharacter()

A character is just the interactive and visual appearance of the player, like the hats, the shirts and everything else. Whenever a character touches a brick only their body parts (head, torso, right arm) will be seen as “touched”.

To get a player from the character you get the character which is part.Parent. You can store it in a variable too. You also need to check if “part” is actually part of the parent. I included that for you.

Your script fixed will be:

function onTouched(part)
     if part.Parent:FindFirstChild(“Humanoid”) then
          local Player = game.Players:GetPlayerFromCharacter(part.Parent)
          Player.PlayerGui.GameGui.SwordShop1.Visible = true
     end
end

script.Parent.Touched:connect(onTouched)

In order to get the PlayerGui with a server script, try using RemoteEvents. Here, let me show you the ServerScript.

1) First, place a RemoteEvent inside ReplicatedStorage.

2) Get the .Touched script and write this;

script.Parent.Touched:Connect(function(hit)
    if hit.Parent:WaitForChild('Humanoid') then
        game.ReplicatedStorage.RemoteEvent:FireClient()
    end
end)

3) Now, place a LocalScript inside of your SwordShop1 and write;

game.ReplicatedStorage.OnClientEvent:Connect(function()
    script.Parent.Visable = true
end)

Voila! I hope I helped. If you don't understand something, then feel free to ask me on the comments.