1. First, sign in to the Admin Center using the same username and password you used when you bought your subscriptions. Then, click on your Profile name. A menu will pop up. Click on the word that says 'Billing'.
2. When you're in the Billing section, look for 'Billing History' and click on that.
3. You'll see a list of everything you've bought with your subscription. Find the 'Download' button and click it to save the bill as a pdf.