How do I get a copy of my invoice / receipt?

You must be logged in as an Administrator of the account. Then you can see the Admin menu on the left hand side.

Select Admin and then Billing on the menu like so

Then click on Go to Stripe Portal

All of your receipts and invoices are at the bottom of this page.

Click on any of the invoices and you should see a page pop up like the one below where you can download your receipt.