1. Open Outlook 2010.

2. Create a new email by clicking New E-mail 

3. Highlight the desired text and right click within the highlighted area. This will open an options menu, click Copy or Cut.

4. Right click on area you wish to paste the copied text. Click one of the following three options presented under "Paste Options".

    a. Left option will Keep Source Formatting.

    b. Middle option will Merge Formatting. 

    c. Right Option will Keep Text Only.