Categories can be deleted by following any of these ways:
1. Open selected category (from ProCoins home screen) and click on the edit icon (pencil). In the newly opened window, click on trash icon. You can either remove category with all related information (subcategories and transactions) or just the category.
2. Active 'Rearrange elements' view by clicking the approprate icon on the main bar (two arrows) in ProCoins home screen. Now you can click on the trash icon next to the category you want to remove. Please note that you will be presented with the same choice as above.