Starting with WP ERP v1.3.6 PDF Invoice will now a separate extension (free) for WP ERP users. Previously, it was integrated into WP ERP's core.
You will need this extension if you are using the Accounting module of WP ERP.
Using PDF Invoice for WP ERP you will be able to download your Sales Invoice and Payment Receipts in PDF format.
To download the extension, simply navigate to WordPress Admin dashboard→Plugins→Add New.
Click on the search filter and type PDF Invoice for WP ERP.
You will see the extension in your search results.
If you have already installed WP ERP core, simply click on Activate to get started.