Depends on the country. In Czechia, some documents (such as the contract about selling/buying property) require verified signatures, where you go to a notary or a post office with your ID card, sign the document in front of them, they note what document you brought to them into a book of signature verifications and stamp the document.

Mail-in voting in my state entails "signature verification", wherein I learned - the hard way - that they do in fact compare the signature on my ballot to some signature they've got stored somewhere to see if it matches.