Method 1
1. Press "Edit" button in main screen.
2. After pressing "Edit", following screen appears.
3. "Delete" button appears after pressing button. You can delete the account by pressing the "Delete" button.
4. You can also delete a folder by same operation as step3. If the folder have any item, a dialog appears as below. If you have no problem, press "OK" to delete the folder.
5. Edit mode ends by pressing "Done" button on top-right corner.
Method 2
Slide you finger to left or right on a account you want to delete. Then a "Delete" button appears. You can delete the account like method 1. You can cancel by pressing blank space.