Select the Mail Format > Editor Options tab :
Select the Advanced tab in the left window:
Scroll down a little, and you'll see the cut options, copy, and paste. In the respective sections, select the drop-down list and Match Destination Formatting to preserve the text format:
Or use the options at Use smart cut and paste :
Basically this is done, from now on you can copy the text from where to email in Outlook, the original format will never change:
The above is a little trick but sometimes helps users a lot in the presentation of documents with Microsoft Outlook. Good luck!