This is an extension to the Invoice Summary Format article - if you have not looked at it yet, please do so before continuing.
Someone with HTML experience should handle the use of code snippets in this article. Otherwise, changing an invoice template may result in errors that prevent the system from generating invoice PDFs.
You can find and edit invoice templates in Settings > Templates > Invoices tab.
You will find three .txt files attached to this article:
Invoice Line Items - Grouped By Account - This snippet can list all accounts in alphabetic order with all their line items under them.
Invoice Summary - This snippet can be used to list the total price per account for all of the invoice's line items. The line items themselves won't be shown.
Example Invoice HTML - This is the HTML code of the example invoice shown in the Invoice Summary Format article. Please note that it may not be well suited for your space and is only included to offer an easy way of testing the functionality.