When you are composing, replying, or forwarding an email in Outlook, you can easily add phonetic guide for the selected text (East Asian characters) in the message body.

1. In the message body, select the east Asian characters you will add phonetic guides for, says simplified Chinese characters.

2. Click the Phonetic Guide button  in the Font group on the Format Text tab.

3. In the Phonetic Guide dialog, please do as follows:
(1) Review the ruby text for each character, and change the ruby text as you need;
(2) Format the alignment, offset, font, or font size of the ruby text in the corresponding boxes as you need;
(3) Click the OK button.
 

Now the phonetic guides are added above the selected east Asian characters.

You can easily remove the phonetic guides from text as follows:

(1) Select the characters with phonetic guide you will remove;

(2) Click the Phonetic Guide button  in the Font group on the Format Text tab.

(3) In the Phonetic Guide dialog, please click the Clear Readings button firstly, and then click the OK button.