Personal signature and seal 12* 18 is enough. The private printing size is about 1.5cm~2cm. Stamps are used as stationery printed on documents to indicate identity or signature. Generally, seals should be dyed with pigments before printing. Those that are not stained with pigment and will appear concave and convex after being printed on a flat surface are called steel seals, and some are wax prints printed on wax or wax or envelopes. Made of metal, wood, stone, jade, etc. The earliest seals that can be seen are mostly ancient seals during the Warring States period.