All journal book entries are listed in this table which are recorded by a document (e.g. an invoice).

Grayed out you can see the book entries which have been generated by the document items (articles, services). They can only be viewed here but not edited or deleted. To change them, edit the items (see Edit document).

Other book entries like payments or discounts can be edited or added here.

You can define your own book entry templates in Order categories under Book entry templates.