To move an item from subcategory to the main category,
More > Configuration > Income / Expenses Category Setting
For example, you want to move the "Friends" item in the subcategory to the main category.
1. Select the "Friend" item in the subcategory.
2. Tab the "Main Category" button on the top-right corner and confirm.
3. You can now see “Friends” has become in the main categories among your other main category items.