25.1.9.1.9 Letting an Initiator Approve a Task

Enable initiators to approve their own tasks when the business process requires it.

By default, a user who initiates an approval task isn't allowed to approve their own request. Even if their username is among the participants as a potential owner, the APEX engine filters out the initiator's username to enforce this common business practice. However, if you need to allow a requester to approve their own task to meet a business requirement, then enable the approval task definition's Initiator Can Complete switch to allow it.