There are four types of invoice for customers in Sedona Office. They are Cycle, Job, Service, and Miscellaneous. Each of these types of invoices allows a different level of alteration of the invoice after the invoice has been made, up until the invoice has been marked as printed.
The sections that pertain to what change be changed when are labelled below.

Part 1 is customer information. The type of invoice, the branch, term, etc.
Part 2 is the line item information. This holds the chargeable items for the invoice as well as the description, contact, and memo.
Part 3 is where the invoice status will be marked.
What can be changed by Invoice Type.
Job Invoice – Job invoices can never be changed once created. They immediately grey out all options and do not allow adding or deleting items from the invoice. This persists after the invoice has been marked as printed.
Cycle Invoice – Cycle invoices lock down any changes to the customer information, as well as editing any line items. However, they do allow you to delete or add additional line items until the invoice has been marked as printed.
Service Invoice – Service invoices allow you to edit any field, including editing line items. They also allow you to add or delete line items. This will lock once the invoice has been marked as printed.
Miscellaneous Invoice – Miscellaneous invoices allow you to make changes to the customer information and line items. They are not locked once the invoice has been marked as printed.