By default the mandatory option for the system fields cannot be removed. In Zoho Recruit, you can remove the mandatory option for the existing and newly added custom fields.

The following are the system fields, where the mandatory option cannot be removed:

Job Openings - Job opening Id, Posting title, Client, Client manager, Assigned recruiter, No.of.positions, Job Opening Status and Vertical.
Candidates - Candidate Id, First name, Last name, Email Id and Resume Status.
Clients - Client and Client manager.
Client Contacts - First name, Last name, Email Id and Client.

Note: Only Recruiter Admin can remove the mandatory option.

To remove the mandatory option:

1. Click [Module] tab.
   Note: Module refers to Job openings, Candidates, Clients and Client Contacts tab.
2. Click Customize the [Module] detail, located at the right panel.
   
3. Place the mouse cursor on the drop-down arrow, and click Edit this field.
   
4. Uncheck the box "Make this as mandatory field", and click Update.