Set up a Japanese input source on Mac
If you set up the Hiragana, Katakana, or Romaji input mode, you can type in Japanese.
On your Mac, choose Apple menu
, then click Input Sources.Click the Add button
, select Japanese (on the left), then select any of the following:Japanese - Kana
Japanese - Romaji
Tip: The Romaji typing method is useful when you’re not using a Japanese keyboard; text you type is automatically converted to hiragana.
Click Add.
After you add a Japanese input source, you can change preferences, for example, to select input modes or show predictive text completion candidates.
Note: If your Mac has a Touch Bar, you can customize the Control Strip by adding the Input Sources button 
. See Customize the Touch Bar.