An approval process is an automated process your organization can use to approve records in Salesforce. An approval process specifies the steps necessary for a record to be approved and who must approve it at each step.

Approval steps assign approval requests to various users and define the chain of approval for a particular approval process.Each approval step specifies the attributes a record must have to advance to that approval step, the user who can approve requests for those records, and whether to allow the delegate of the approver to approve the requests. The first approval step in a process specifies the action to take if a record does not advance to that step. Subsequent steps in the process allow you to specify what happens if an approver rejects the request.

Cheers!!!