There are three common reasons that a job would not be added to an invoice even if all of the other requirements are met:
1. The job has already been invoiced
A job cannot be invoiced more than once. If you need to change which invoice a job is associated with, you will first need to detach that job from its current invoice. Once you have detached it, you will be able to re-invoice it.
2. The appointment requires a signature and is unsigned.
If you need to invoice an appointment without a signature (when one is required), the best option is to upload a blank page to the signature tab. Once there is something uploaded, you will be able to invoice the appointment.
3. The job is a cancelled appointment with a $0 charge
If you wish to include cancelled appointments with $0 amounts, click Advanced on the create invoices screen and check the box for Include Cancelled Appointments with $0 Amounts: