You can legalize your signature under a document at the municipality. With this, the municipality declares that the signature is genuine.
Legalizing a signature is often necessary on documents that have to be sent abroad. Even if you give your consent for something, legalization may be necessary.
You sign the document or a copy of your passport, driving license or identity card in the presence of the official. The municipality confirms with a stamp that your signature is the same as the one on your passport or identity card.
The value of the stamp on your document
A legalization says nothing about the correctness or reliability of the document. The stamp of the municipality only proves that the signature is of the person named in the document.