The Student Enrollment ID number (Register ID) is not listed anywhere on the front-end of the application. However we can pull this information in Advanced List. 
Each Year a User is Enrolled in School there is a Enrollment Row created for the Student. In this record lives a Registration ID

To Create a List to Pull Student Enrollment IDs: 
  1. From any module select Analysis > Manage Lists 
  2. Select Manage Basic and Advanced Lists 
  3. Select List Templates
  4. Select the category: Constituent Information
  5. To the right of list: Registered Students (Current Year and/or Next Year) select View/Copy 
  6. In the Display Field tab select "Select Fields" to add a field
  7. Select the + icon to expand User Register
  8. Select Register Id by marking the blank radio box beside > Select 
  9. User-added image
  10. On the Filters tab
  11. Change Filter to User Register.School Year is any of 20XX-20XX (select the year(s) you are looking to display)
If you are looking to find the Register ID for a Specific Student: 
  1. Add another Global Filter by selecting the + button
  2. Select User Base.User ID in the list
  3. The operator will be "Is Equal To" > Enter the ID of the User you are looking for 
User-added image