Description :
In Odoo 17, states play a pivotal role in indicating the different stages or statuses that records can undergo within the system. These states are commonly represented as selection fields in Odoo models, allowing users to easily discern the current status of a record. To append new states without altering the existing ones, the selection_add attribute comes into play. This attribute enables developers to append additional options to an existing selection field without the need to modify the original definition of the field.