Many attorneys will have had trouble copying redlined text generated with document comparison software from a Word document into an Outlook email message. Here's how you can do it.
In Word, under File . . . Options . . . Customize Ribbon, confirm that the Developer tab is checked off.
On the Developer tab, click on 'Design Mode'.
Select the text that you want to paste into an email message.
On the Developer tab, use the option to group the selected text.
Select the text again, and then right click and click 'Copy'.
Paste the text into a new HTML formatted email and it will be shown with track changes.
See these steps demonstrated in this gif: