Microsoft branding terminology for an Azure offer to run HANA instances on SAP HANA hardware deployed in Large Instance stamps in different Azure regions.
This is not an SAP support forum. but according to the SAP documentation: https://blogs.sap.com/2021/06/10/how-to-generate-a-new-s-user-id/
https://blogs.sap.com/2021/03/09/learn-all-about-s-user-ids/
You can create an S user and authorisation with a super administrator account.
It sounds like this needs to be done within SAP by an authorised user.