As soon as you will be charged for your pro plan, we are going to send you an email with the payment confirmation and the related invoice to the email address associated with your account.
You can also check the billing history on the My Pro Plan section and click on the "Resend Invoice" button if you missed our message somewhere in your inbox!
Tip: If you need a pdf version of the invoice, just right-click on the email text, select "Print" and then save it as pdf.