You can access and download past invoices by visiting the billing history section of the billing tab on the Settings page of the Fulcrum web app.
The invoices are sorted by date with the newest at the top of the list.
They can be downloaded by clicking Print to generate a PDF copy. These receipts are also sent to the billing email addresses you have on file as email attachments when processed.
If your plan is being invoiced and not being automatically charged, you will need to reach out to firstname.lastname@example.org to obtain a copy of any past invoices.