There is no form or formal requirement for voluntary disclosure. The written form is always preferable in order to preserve evidence.
The taxpayer must declare all amounts that are not time-barred and have not yet been declared in full. Partial voluntary declarations (either not all years or not all tax types or not all) are invalid. If 5% or more of the income is not reported in the first declaration, the entire voluntary disclosure is null and void. The tax office must be in a position to issue tax assessments immediately on the basis of the voluntary disclosure that do not understate taxes.
A voluntary disclosure is excluded if the tax office has already discovered the offense in whole or in part and the offender knew this or should have expected it.
The voluntary disclosure is only exempt from prosecution if the evaded taxes, interest and any surcharges have been paid within the (short) deadline set by the tax office.
Read here why black money is not worth it.
If you would like to know how we can support you with your voluntary disclosure, click here.
