4chan

I think you meant last/family name :p

The answer is that they can't.

It used to be an obligation to change your name to your husband's and the civil code reform made it so the government only interacts with people using their birth name when it comes to their civil rights, only those married before the 2nd of April 1981 were allowed (but not forced to) keep using their married name. The change was asked for by women at the time and most that were married before 1981 started using their maiden name as time passed (both my 90 y.o. grandmothers do for example).

So you can't legally change your name to your husband's, you're still free to call yourself whatever you want but it won't match your ID.