Type roman strings using hiragana or katakana on Mac
After you set up a Japanese input source, you can convert hiragana to roman characters.
Automatically type common roman strings
When you type well-known roman strings that contain punctuation, such as http:, www., and file:, they’re automatically converted to roman characters using the Romaji input mode.
On your Mac, switch to a Japanese input source.
In an app, type a common roman string (such as http:).
Press the Return key to confirm the conversion and return to the input mode you were using.
For example, if you’re using the Hiragana input mode and you type “koreha,http:” (これは、hっtp:), when you type the colon (:), the input mode changes to Romaji; when you press Return to confirm the conversion, the input mode reverts to Hiragana.
Use Windows-like shortcuts to enter Romaji mode and type roman characters
On your Mac, switch to a Japanese input source.
Click the Input menu in the menu bar, then choose Open Japanese - Kana Settings or Open Japanese - Romaji Settings.
Click Japanese - Kana or Japanese - Romaji in the sidebar, then select “Windows-like shortcuts.”
In an app, press the Shift key as you type any letter to enter Romaji mode. In Romaji mode, text you type is entered as roman characters.
Press the Return key to confirm the conversion and return to the input mode you were using.