What is the difference between a submitter and approver in submittals?

In Procore's Submittals tool, you can designate an approver and a submitter in a submittal workflow:

• Submitter: The Submitter role on a submittal in Procore is typically filled by a subcontractor that needs to submit a submittal for approval before that scope of work can begin. 
• Approver: The Approver role on a submittal in Procore is typically filled by a member of the design team (i.e., an architect and/or engineer) and the project manager. These users are typically responsible for reviewing the submittal before its scope of work is deemed "acceptable" for the project. Once all approvers have reviewed and approved the submittal, the submittal can be closed out, marking it as approved for construction. All approvers need at least 'Standard' level permissions on the Submittals tool.