How to record the audio of 'Read Aloud' feature?

Good day Utkarsh, thanks for your question. I am glad to be able to provide assistance to you today. You can try to record it by using an extension in MS Edge like this one https://microsoftedge.microsoft.com/addons/deta... or you try using Audacity but you will not be able to use that for monetary purpose as it is not meant for commercializing and it can only be used on a personal matter.

"Use of clip art and other media found on Office Online or provided by Microsoft product is governed by the Microsoft Services Agreement and the EULA (end user license agreement) for the product from which you obtained the media. Find End-User License Terms for Microsoft products. If your use falls within the scope of these guidelines, no further permission is required from Microsoft or third parties.
Sample Media includes images, music, etc. customarily found in the "sample" folders within Microsoft operating systems. Sample Media may be used for personal use only. You may not sell, lease, or distribute Sample Art, or any materials you create that use Sample images, for any commercial purposes."

Reference links:
https://www.microsoft.com/en-us/legal/copyright...
https://www.microsoft.com/en-us/legal/copyright

Regards,
Paul R.