You’re required to show proof of income and expenses to the Tax and Customs Administration (belastingdienst). That’s why it might be useful to keep an account book.
If you’re working on the streets, the Tax and Customs Administration considers you an entrepreneur. This means you’re obliged to pay taxes.
You could also work as a paid employer, or through opting-in (for example at a club or as an escort). Working as a paid employer means taxes are calculated into your salary by your employer.
Opting-in is often possible at a club or an escort agency. Opting-in is also known as ‘working under terms and arrangements’. Roughly most employers offer opting-in, which means they are paying your payroll taxes. Though you’re not officially a paid (payroll) employer, they do provide you with income statements.
Mind you, you’ll still need to file an income tax return annually. Should you consider working through opting-in, a registration address and a citizen service number (burgerservicenummer) are mandatory.