Before we begin you will need to install the Japanese language pack. This way you will be able to type Japanese. I will outline the steps to installing it here. First, open Windows settings by clicking the start menu and typing "settings", Then click settings. Next, click "Time & language" then click "Language and region" as shown.

Next, click "Add a language" and then search for Japanese then select "Japanese". Finally, click install. Now that you have the Japanese language pack installed. You can type in Japanese by clicking the button in the bottom right side of the task bar. The button by default will usually read as "ENG". Clicking it will swap input methods to Japanese, allowing you to type Japanese now.