A requestor (not included in hierarchy and has no approver rights) creates and submits a requisition but obviously it will be in incomplete status, our requirement is to submit a requisition to hierarchy or first approver after a requestor submits it for approval.
Mentioning that we dont want to use document type option "can change approval hierarchy" as it will require requestor to select values from list of hierarchies and then departments/ persons.
It can be solved by creating an approval rule in Approval group.
For example, create an Approval group with Approval rule, select a particular item category (low and high value) with OBJECDT ITEM Category range and TYPE include. Assign this approval group to a employee by position or supervisor hierarchy. When a requester rise a requisition for an item which belongs to that particular category the approver will be selected as per the approval rule.