It is best to have a round seal (although a square seal is also acceptable, the Japanese use a round seal), and the size is one centimeter in diameter. You can prepare more seals, but one of them must be made of hard materials, such as plexiglass, horn, jade and so on. This kind of hard seal will be used when you go to the bank to handle the account, because the words printed by the hard seal will not be deformed, and every time you withdraw money from the account, they will scan your seal on the withdrawal slip. It is better to prepare an electronic seal, which is more convenient to cover when it is not very important, because there is no need to print mud. You'd better prepare these seals before going abroad. Although going to Japan can also be engraved, after all, the phone bill is relatively high, so it is better to prepare in advance.