Whereas sequential approvals process as a single thread in a row or stages, parallel approvals happen independently. A vacation request may also take the form of a parallel approval: you may need two individuals to approve time off (such as your immediate manager as well as an HR representative), but those individuals might be in different management or reporting structures and their approval processes are independent of each other.
Parallel approval processes allow different branches of approvals to happen independently. Logic at the end is used to evaluate whether the overall approval is successful or not.
