Under which menu option of a word processing program does a callout appear?

Shapes

Explanation:

The Menu option of a word processing program where a callout will appear while using a word processing program is the SHAPES option.

This menu option can be found under the tab option of INSERT. callouts are represented with shapes with texts in them or with arrows and pointer  and are used to draw attention of a reader to a particular information in document by the Author of the document. the use of callouts are used when very sensitive information in a document might be missed by the reader.

Authors who use this feature are usually writing for a very specific purpose of passing essential information embodied in a document.