Invoices and Receipts
You can always access your billing invoices and receipts in your account by click on Account, then under the Billing tab:
Just scroll down to the Invoices section to find all your past invoices and receipts:
Exporting to PDF
To export an invoice to a PDF, you can click on a specific invoice date to navigate to the invoice page, right click, then click Print and select the Save as PDF option to export it to a PDF.
You can also use Control + P (on Windows) or Command + P (on Mac) to also pull up the printing options.