Make phone number required for user register

How do I make the phone number required when a user is registering AND when a user is posting a new job and registering at the same time?

If I go to Theme Options > General Setup > Registration, I can add a new Field. However, this makes 2 phone number fields in a user’s member account details since there is already a field for phone number in there. Second issue is that even though I have this New Field required, it does not show up when a user is registering and posting a new job at the same time.

See http://www.padutchcontractors.com/post-new-job

Thanks,