If you want to add a quick task (just the title), you can use the Quick Add at the bottom of the screen. That will help you add new tasks in no time: tap, type, and click “Done”. Yes, it’s blazingly fast.
If you want to include some other fields just click the "+" button. A new window will appear with the fields: Title, Description, Due Date, Star, List Tags, Start Date, Repeats, Energy and Time. Fill in the info, at least the Title, and click “Save”.