To enable or disable Natural Language Parsing in iOS, open an editor as if you were going to create a new event or task and swipe right to left in the title field. If NLP is on, you will see Title (or event description). If NLP is off you will just see Title.

To see how to enter things into NLP to have them automatically show up in their desired fields, check this FAQ: https://webis.helpshift.com/hc/faq/48-quick-entry-for-tasks-events-using-nlp/