To begin, click the Settings gear and then Jobs. You will see Cancellation and Postponement reasons:
You are now able to choose whether the Cancellation reason applies to the Invoice (Job) or the visit.
You can select one or the other, or both to have the option to use each option for both the job and the visit.
Please note that you Cannot cancel a job that has any Proposals on it that have already been accepted, if a payment has been taken and has not been refunded or there are any visits with a status past the point of "scheduled".