If you create a new subcategory by mistake, or want to delete a previously created subcategory, you can do so at any time. If you have any transactions assigned to this subcategory, you will need to select a new category to assign those transactions to.

1. Tap any transaction 
2. Tap the Category field
3. Tap the + sign next to the main category that the subcategory belongs to
4. Tap the Trash icon next to the subcategory
5. A pop-up message will appear to confirm that you do want to delete the subcategory
6. Tap Delete