In Field Options, you can set default privacy settings for profile fields. Privacy settings determine the profile fields that are visible to other members of the community. If a field is public, all website users can view it. If a field is private, only the individual website user can view it. 
Users can set privacy settings for their profile information in the Profile Form part.

Set the default behavior for maintaining the privacy of constituent data on your website. These settings determine which profile fields are visible to other members of the community, when no explicit privacy preference is set by the user.

Note: The user’s settings overwrite the default privacy settings in Field options. For example, Home Phone may be marked Public By Default in Field options, but users can make their phone numbers private on the Profile Form part.

To make the default public or private by default:
  1. Log in to the NetCommunity website
  2. Navigate to Administration>Field Options
    • To make a field public by default: Mark the Public by Default checkbox next to the desired field
    • To make a field private by default, Unmark the Public by Default checkbox next to the desired field
  3. Click Save
Additional Resources
How to set privacy as an individual
How to change privacy of fields to public or private in a directory