There are many documents in Japan that require a personal seal.
I had a personal seal made when I came of age at 20.
I need it to open a bank account.
We use personal seals when we recieve our packages.
They say such seals date back more than 5000 years, to acient Mesopotamia.
The concept made its way to Europe and China, then Japan.
In these days, there are vorious design of seals.
They are able to use as official seals.
There are more cases in which a signature is acceptable,
but you may order your own seal, you can enjoy Japanese style more.