The primary control of fields is managed in the plugin’s Fields tab. Any field included in that table is used as a user field.
If “registration” is checked, the field is included in the registration form, user profile, and the user’s view of the user profile page.
If “registration” is unchecked, the field is “admin only”. It will not display in the above instances, but it will display in the admin’s view of the user profile.
If you want to remove a field from the user-facing view of the user profile (i.e. the [wpmem_profile] shortcode profile view), you can filter out the field from the fields array. Here’s a code snippet example of how to so that: https://rocketgeek.com/code-snippets/remove-a-field-from-the-profile-update-form-but-not-the-registration-form/
The 3.5.0 version of the plugin will add the ability to control the above view via the Fields tab. This will be released as beta sometime during the next few weeks.