Creator : A creator is responsible for creating a design and/or content campaign/task. After completion, he/she can send it to the reviewer to review the work done.
Reviewer : A reviewer is responsible for reviewing the campaigns submitted by creators. They can send it to an approver or can send back to the creator for changes.
Approver : Post approving, he/she can send it back to the reviewer for changes or queries. The reviewer then backtracks it to the creator for making the said changes.