Invoices

I filled the payment method (debit card) and purchased an item from iTunes.

I received an invoice in my email, saying it is billed to my address.

Isn't the cost of the item deducted from my debit card balance?

If not, how do I make payment?

I'm kinda afraid since I assumed the cost of the items purchased from iTunes would automatically be deducted from my debit balance for the past few years.