at learning admin resp. when we search for enrollment subscription in learning history, the last entry is One time event, there is no create button with that. What is the use of this? Where do I create such one time events?
As Anders said, One Time Events are no longer used - that's why there's no 'Add' button. If you had been using OLM for a long time (back when it was OTA) you may have used One Time Events as they used to be something you could use. This region of the page is only for customers that previously used One Time Events. If your organisation does not use these, I would recommend you personalise off that region if possible.