There is currently no Average Daily Hours field in the Candidate Hire form in Recruiting. However, this value is automatically carried over to the employee profile upon hire if it is defined in Org Setup > Jobs and Job Assignments for the job assignment that you are hiring for. If it isn’t defined for the job assignment, you can manually add it to the Average Daily Hours field of the Job Requisition form or the Job Assignment Details section of the job requisition's Details tab. If added to the job requisition, it will automatically carry over to the employee profile upon hire.
The value that you manually enter in the Average Daily Hours field of the requisition details only carries over to the employee profile if you select the same job assignment in the Candidate Hire form. For example, if you select a different job assignment in the Candidate Hire form, and it has different average daily hours or no average daily hours, this new value is carried over to the employee profile instead of the value that you defined.