Add and delete reminder lists
All reminders you create are put into a reminder list. iCloud Reminders comes with one list for active reminders, and a list for completed items. These lists can’t be renamed or deleted, but you can create additional reminder lists. Organizing reminders into lists makes it easy to keep your work, personal, and other to-do items separate from each other.
Create a new list
Click the Add button at the top of the window, above the reminder lists.
Type a name for the reminder list in the text field that appears, then press Return.
Delete a list
When you delete a reminder list, all the reminders it contains are also deleted. You can’t delete your last reminder list because you must always have at least one list for active (not completed) reminders.
WARNING: When you delete a reminder list, the list is deleted on every device where you turned on iCloud Reminders. For example, if you have iCloud Reminders turned on on your iPhone, when you delete a reminder list from iCloud Reminders on the web, the reminder list is also deleted from the Reminders app on your iPhone.
Select the reminder list you want to delete.
Press the Delete or Backspace key.