Each of your Nucleus receipts is stored directly within your Nucleus account so you can always easily access and download past receipts.
Begin by hovering over the 'Account' button in the top right corner and select 'Subscription' in the dropdown menu.
Scroll down to the bottom of the page to find 'Billing History'. There, you'll find each of your past Nucleus receipts. To download a receipt and save it to your computer, simply click on the download icon for the corresponding receipt.