In the Reminders app .
Delete a list or group and their reminders: Swipe left on the list or group, then tap , tap Sort By, then tap Manual.
When you sort or reorder a list, the new order is applied to the list on your other devices where you’re using upgraded reminders. If you sort or reorder a shared list, other participants also see the new order (if they use upgraded reminders).
In the search field above the reminder lists, enter a word or phrase.