In order for an Event Registration to populate in the Events section on a candidate's record, the registration form must have the Candidate Event Type selected.

To add an Candidate Event Type to your Registration: 
1. Navigate to Enrollment Management 
2. Events > Events Registration Form 
3. Select Edit to the right of the appropriate Registration Item
4. Under the General Info Tab select the appropriate option in Candidate Event Type drop-down 

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If you do not have any options in your drop-down or need to add another option see: How to add an event type for onBoard

Note: If the registration has been submitted, you can still make this change before processing and the event will populate.