Marking a Contact as Personal means that you allow that Contact to receive the personal contact information you record in your Personal Profile.
Personal Contacts are denoted throughout the app with a HEART icon.
To mark a contact as Personal, from Contacts, hit the HEART icon.
From Contacts, click edit then Add/Remove Personal.
Don't forget to check out UCM on YouTube. Here are our videos on How to Share Personal Information with Contacts:
And more videos on How to Manage your Profiles: