You can access your invoices from your Billing Dashboard, to access the Billing Dashboard you must be the Team Owner or an Admin on the account:
Click view invoice to open the invoice:
You can download and save this invoice as a PDF 👍
If you upgrade/downgrade mid billing period you'll be charged/credited the difference and a new invoice will be generated to reflect the change. Any positive account balance will be applied on your next billing cycle.
Updating your Invoice Settings:
You can edit your invoice settings at anytime from the Payment Method tab on your Billing Page
If you're in the EU be sure to enter your VAT number in here 👍