If you marry in a civil registry office in Germany, after the marriage the registry office will send the details of the marriage to the relevant residents' registration office. The registration office, in turn, transmits this data to the tax authorities. According to the law, the tax authority first assigns to both spouses the tax class IV. These information details are then stored in the ELSTAM database, from which the employers obtain the data for the correct payroll tax calculation.
If you marry abroad, you have to inform the registration office and the tax office after the marriage by yourself.
However, if the tax class IV is not the best option for both spouses, then you must use a form to apply to the tax office to change the tax class to tax classes III and V OR to use the work-factor method.
It should be noted, however, that if both spouses
1) are employees AND
2) have no further taxable sources of income AND
3) have the tax class IV,
then they are not required to file a tax return every year.
IMPORTANT: Ask your tax accountant to verify that it is not worth your while to file a tax return in the year of your wedding.
Those who choose tax classes III and V or the work-factor method are required to file a tax return. The obligation to file a tax return exists as well for all those who receive freelance or commercial income or income from renting, leasing, pensions, etc.