How to enable the Japanese keyboard on Windows, Ubuntu, Mac and more
Jump to your platform by clicking on one of the links (other platforms are coming soon):
First you have to open your Settings.
Open the Text & language menu.
Click on the Region & language category.
Now select Add a language by pressing on the + sign.
Then, a view opens with all the supported languages. Here you have to scroll to the right and select 日本語 Japanese entry.
Windows will notify that it'll install the necessary packages. You'll know when it's finished when it says Language pack available on the second line.
Now you can select the Japanese keyboard in the task bar in the bottom right corner. Click on your current language (here ENG) and select Japanese Microsoft IME.
There should appear an A character next to language selection menu.
Click it exactly once and it should switch the hiragana character あ.