While you can configure a default message format for composing new messages, Outlook will always reply in the same format as the original message.
From a compatibility and layout maintaining point of view, this makes sense. However, on some occasions, it also makes sense to “upgrade” the message format from Plain Text to HTML.
While you can manually change the message format after pressing Reply, you could be left with the wrong font settings and your Plain Text signature would have been added rather than your HTML signature.
The macro in this guide will let you reply in the HTML format as easy as pressing a “Reply in HTML” button.
Continue reading: Always Reply in HTML