Before you start: you need Create or Add to Invoices permission, which allows creating an invoice from the cart or adding items to an invoice.
Adding products
Open the invoice in Back Office.
Scroll to the bottom of the line items and select Add item.
Search for the products you want and select them. Each row shows a thumbnail, quantity, and tax as you build the list. Only products from facilities you have access to appear.
Choose Add to invoice to add the items and leave the balance for later, or Add & charge to add them and open the charge flow.
What Add & charge collects
Add & charge opens the charge flow with the amount prefilled to the items you just added. The amount is editable — if the invoice carries an open balance, you can raise the figure to collect more than the new items.
Where Add item is not available
Anonymous invoices
Voided or refunded invoices