How to perform mass update employee and user account email address in single shot ?

Summary

How to perform mass update employee and user account email address in single shot ?

Content

We have the below mass update requirements for employee information in HCM.  Kindly help us.

1. To update the existing work email address of the employee for bulk transactions that should be updated in the OIM as well..

2. To create employee/user account in the system with different email id as presently work email address is created as user account in Oracle.