The Working Holiday Visa is a special type of visa only available to select countries. It allows you to stay in Japan (日本) for 6-18 months (depending on the country). While there, you can work and study pretty much anything.
Depending on your country of origin and the purpose of your visit, you will need to get a Japanese visa before entering Japan (日本). I’m sure most of you have heard the term “visa” before, it’s basically your entry ticket