What is a wedding water label?

In ancient times, "water sign" refers to the wooden board painted white or black that the store hangs on the wall. It is mainly used for prompting information (such as price and catalogue) and recording important things (such as arrival time and room number of guests). That's a signboard, commonly known as "water sign". In addition to the above functions, the wedding water sign also plays an indication role now, so it is also called "welcome sign", "sign" and "guide sign".