How can I add a comment in word in a text box?

When I highlight a piece of text and try to add a comment to it, the "New Comment" button is grayed out. This occurs in a text box. How can I add a comment?

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Solution 1:

Insert a Frame instead of Text Box, then you can add comment to it. You can add Insert Frame to the Quick Access Toolbar (All Commands) and use it to draw a frame around selected text. After that use New Comment to write a comment.

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Click Here to Add new command to Quick Access Toolbar