Task status once accepted
From Planfix
When a task has the status New (task status), it contains Accept and Decline buttons. These buttons allow the assignee to accept or decline the task:
The setting Status assigned to tasks after clicking "Accept" lets you choose the status the task will automatically be transitioned to once it has been accepted.
This setting is located in the upper part of the additional settings for status sets:
Additional information
By default, a task's status is changed to In progress once it has been accepted. Each process has its own status set, so you can manage the task status once accepted at the process level.