International Phonetic Alphabet font needed

When you enable "Show keyboard and emoji viewers in menu bar" a new rectangular icon will appear in the menu bar. Click that icon and choose "Show Emoji and Symbols". There will be a gear icon in the top-left of the window that appears. Click the gear and choose "Customize List". In "Select categories" click the triangle to the left of Symbols to expand the list, then scroll down and enable "Phonetic Alphabet". Then click the Done button

You can find these characters in the Emoji & Symbols display.

If you don't already have this, go to System Preferences > Keyboard > and check "Show keyboard and emoji viewers in menu bar"

Then, if you click the gear icon in the top left corner, you can add "Phonetic Alphabet" to the list.

Open the "Character Viewer" icon in the menu bar and choose "Show Emoji and Symbols". Select "Phonetic Alphabet: in the left column. Leave the window open and go to whatever app you are using that needs the symbols. Whenever you need a phonetic symbol, just double-click it in the "Character Viewer" window and it will be inserted into your text.

International Phonetic Alphabet font

You may find something useful among the links listed.

Sorry. See Malcom’s answer for the important step I missed.

If you do a lot of such input, this app may be useful:

https://blugs.com/IPA/index.html