Fixed expenses
These include rental payment, mortgage payments, utility bills, household expenses like groceries and food, insurance premiums, school fees etc.
Variable/unexpected expenses
These include unexpected expenses, like vehicle maintenance, additional fees, medical bills etc. You will not be able to budget for these, but it is important to track them so that you understand how much is being spent on such items.
Debt expenses
These expenses include loan repayments/ installments; credit card bills etc.