Moon Invoice allows you to create categories for expenses. Here are the details below.

1. Open the Moon Invoice application on your smartphone or tap this link.
2. Firstly, add expenses by tapping on Purchases > Expenses.
3. While adding an expense, select an existing category or type a new one.

4. To view used categories, go to Settings > Categories > Expense Categories.

                                                                                                                                       - Moon Invoice