If you have a paid HelloSign or HelloFax subscription, team admins can find a monthly or annual receipt within your Account Details page. To get there, find your email address in the top right corner of your screen and click on the arrow next to it. Then click on Settings. Once that loads, click on the the Billing tab at the top on the right.
"Billing Information" will be the third row of options, you'll see "Receipts and Invoices" at the bottom of the page. An example:
Admins can also add an address or edit the address that will appear in your receipt/invoices. You can add or edit this from the same Billings tab in your settings.