How do i fix " Expected identifier when parsing expression, got )"?

You added a () at the end in the "end" function. You are not supposed to do that at all in Lua. You can only write "end)" and it is only used when closing a function that starts with "(function". For example:

script.Parent.Touched:Connect(function
	--Function goes here
end)

Anyway here is the answer:

local adminReward = script.Parent.Parent.Parent 
local adminNameHolder = Script.Parent

if game.Players.LocalPlayer.UserId == "1371309169" then [[-- When typing "userid" in Roblox, you always have to write it like "UserId". This may not be true every time, but it is a learning experience that I got when trying to define "UserID". Hopefully, that tip helps in the future! :) --]]

	adminNameHolder.Text = "Hey M!" 
	adminReward.Enabled = true 
elseif game.Players.LocalPlayer.UserId == "548321187" then 

	adminNameHolder.Text = "Hey L!" 
	adminReward.Enabled = true

elseif game.Players.LocalPlayer.UserId == "131427586" then 

	adminNameHolder.Text = "Hey W!" 
	adminReward.Enabled = true 

end 

Hopefully it helped!