Onboarding Requests Report

I was able to achieve the functionality with the following steps.

1. Date of Joining is a Onboarding form field. I created a new field called Hiring Date in the ticket form and hide the field without any condition.
2. Created a new workflow to copy the Date of Joining to Hiring Date whenever any Onboarding SR is created or updated.
3. To implement step 2, I used expression builder in the WF to extract the Date of Joining using the following expression,  date(year('{{ticket.onboarding_request.actor_1.cf_date_of_joining_iso}}'),month('{{ticket.onboarding_request.actor_1.cf_date_of_joining_iso}}'),day('{{ticket.onboarding_request.actor_1.cf_date_of_joining_iso}}'))
4. In the next step set the Hiring date with value from expression step.
5. Now as Hiring Date is a normal ticket field, I could create the report with filter criteria as Hiring Date = Today.