Use this function to create a preliminary invoice based on invoiceable transactions.
Note! Unique invoices will be created for invoices lines which belong to projects which have the Project Unique Billing option enabled in the Project window. For such invoices, the Project ID field on the invoice header will automatically get the ID of the project.
The transactions you want to include on the Invoice, must have the status Invoiceable.
As a result of this entry, an invoice with preliminary status (and a preliminary Invoice Number) is created. This invoice is now ready to be released.