Every time a payment is made, you will be emailed an electronic receipt of the transaction. Additionally, you can find your payment history by going to Billing Settings and selecting invoices. You will see a list of past payments and can click on any of them to download a PDF invoice of the payment.
You can also use this button to access your billing settings and review your past payments.
You will need enter your email and verify with a one time password that will be sent to you.