This is when you work without an employment contract, do not pay taxes, and do not receive social guarantees.
This is when you are not entitled to vacation, sick leave, pension, or social insurance.
This is when you cannot protect yourself from the employer's wrongdoings.
This is when you work for yourself and him, not for yourself and the country.
Do not agree to undeclared work, because you lose more than you earn.
Declared work is your future and your dignity!