By default, it is not possible to delete invoices. However, you can enable the deletion of incoming and outgoing invoices separately for each company.
Procedure in the FM Portal
Path to the starting point: System Settings - Basic Data - Basic Information - Companies
Open the company record for which you want to enable invoice deletion.
If you want to allow the deletion of incoming invoices, enable the "Allow deletion of incoming invoices" option in the "Incoming Invoice Settings" section.
Invoices for this company can now be deleted until they are posted to the posting journal.