If entire sections of the Constituent360 record are missing, then more than likely this has to do with the Standard Page Center settings for the "Constituent Profile".  To restore the constituent record sections and fields, follow the instructions below:
  1. Go to Setup > Standard Page Center (If you do not have this option available, please contact support or an advanced site administrator to make this change for you)
  2. Next to, "Constituent Profile (Admin-Side User Registration)," click Customize
  3. Check the box next to every constituent field you would like the admin to be able to see (or click Check All under each section) followed by clicking Next
  4. Check the box next to every constituent field you would like to make required when an admin is creating a new constituent, followed by clicking Finish
  5. Repeat the steps 2-4 for page, "Constituent Profile (Admin-Side User Update) "