How do you make a script for in game currency ( Not robux) to be sent to the player?

First of all, you will need to make a leaderboard. Once you're there, you change the value to whatever you want to add it to. I'm assuming you don't know how to make a leaderboard, so I'll give you a bit of code and you should be able to script it from there.

game.Players.PlayerAdded:Connect(function(plr)
	local stats = Instance.new("IntValue")
	stats.Name = "leaderstats"
	stats.Parent = plr
	
	local currency = Instance.new("IntValue")
	currency.Name = "Money" -- change this to the name of your currency
    currency.Value = 0 -- change this to the starting amount of cash
    currency.Parent = stats
end)

If you really still don't know what to do, I highly suggest searching up loops on the Roblox API Reference (the guide).

Hint..!

for i,v in pairs(game.Players:GetChildren()) do
	v.leaderstats.Money.Value = v.leaderstats.Money.Value + 10
end

(In the future, please try coding it before posting on this website)