After you purchase a WordPress plugin or theme from WPDeveloper you can print invoice for them separately. In this doc, you will learn how you can print invoice for your purchase.
Even if you haven't visited our website before, but are using one of our WordPress plugins or themes, for example, NotificationX or BetterDocs, after you purchased their PRO plan an account was automatically created for you on WPDeveloper Website. Use this URL to land on your Account Page. https://wpdeveloper.net/account/
Here is a quick Doc on how to seek Support from the WPDeveloper Team.