There is no form and no formal regulation for self-disclosure. The written form is always preferable for keeping evidence. The taxpayer must subsequently declare all amounts not subject to the limitation period and not declared previously. Partial self-disclosures (either not all previous years or not all tax types or not all income) are invalid. If even 5% of the evaded tax is missing, the complete self-disclosure is invalid. On basis of the self-disclosure, the tax authorities must be in a position to immediately issue tax assessment notices. A self-disclosure is impossible if the tax authorities have already detected the offense completely or partially and the offender knew about this or had anticipated this. The exemption from punishment occurs only if the evaded taxes, interests and any surcharges are paid within the (short) time imposed by the tax authorities.
Why black money is not woth it, you can read here.
If you want to know how we can aupport you in self-disclosure, click here.