Paperform allows you to customize the details of future invoice receipts.
To get started, navigate to your Billing Settings and select the button labelled "Billing Portal".

The page that appears will allow you to modify your Billing Information, including any Tax ID numbers you'd like to add or change.
Company Information
You can also add your company details in the Billing Portal under the "Account Information" tab.
Invoice receipts generated before June 2021 will not appear in your Billing Portal. Instead, you can access and modify these within your Account Settings, under the "Receipts" section. Click the button labeled "Customize Receipts" on this page to get started.