Copy an item into a certain players backpack?

Hello,

I have a variable with a players username, how do I place the item in their backpack?

https://gyazo.com/9ead9101f8a54cf44ff75a0b7fc735f7

while true do
	wait(0.01)
	reciever = script.Parent.UserBox.Username.Value
	game.Lighting["Card"]:Clone().Parent = game.Players.reciever.Backpack
	script.Parent.Parent.Username.Value = ""
end

Thanks, Ethan!

Its best to use a local script for this Put the local script in playergui or starterpack or starterplayer

	local reciever = "RecieverName" -- Put it to the reciever name
	local player = game.Players.LocalPlayer
	game.Players.PlayerAdded:Connect(function() -- Whenever the player joins the server
		if reciever and player and player.Name == reciever then
   			game.Lighting.Card:Clone().Parent = player.Backpack
		end
	end)

If this answer worked then Please submit this answer

From your comment on sal, I have configured it for you a different way. This way, you have a textbox and every time you enter text it looks for that player and awards them the card if they can be found and they don't already have it. If it's not exactly what you're envisioning, I'm sure you can configure it back with the errors that have been explained. Please take a look at this screenshot to see how your hierarchy should look.

-- LocalScript

local ReplicatedStorage = game:GetService('ReplicatedStorage')
local sp = script.Parent
-- Use WaitForChild() on children
local reciever = sp:WaitForChild('TextBox')
-- I'm assuming a Username Value is inside the player?
-- Use ReplicatedStorage if LocalScripts need to access something
-- Use ServerStorage only if scripts need to access something
local card = ReplicatedStorage:WaitForChild("Card")


local function player_hascard(player)
	-- Make sure they don't already have a card
	local inbackpack, equipped = player.Backpack:findFirstChild("Card"), player.Character:findFirstChild("Card")
	if inbackpack or equipped then 
		return true
	end
	return false
end

local function return_player(player_name)
	-- Make sure they exist
	-- GetPlayers only returns objects that have the 
		-- ClassName Player
	-- Use GetPlayers() not GetChildren()
	local found = false
	for i,v in pairs(game.Players:GetPlayers()) do 
		-- if player_name == the name we just looped through
			-- Then we found the player from the textbox text
		if player_name == v.Name:lower() then 
			-- if that player doesn't already have a card
				-- make found = that player and break the loop
					-- and return that player
			if not player_hascard(v) then 
				found = v
				break
			end
		end
	end
	return found
end

-- Use the changed event to detect change in something
-- While loops cause lag
-- Use 'C'onnect, 'c'onnect is deprecated (not supported)
reciever.Changed:Connect(function()
	local find_player = return_player(reciever.Text:lower())
	if find_player then
		card:Clone().Parent = find_player.Backpack
	end
end)