Let’s try these steps to make changes in both type of mails.
Font Style for new messages:
1. Open “MS Outlook”.
2. Click on “File” Tab >> “Options” >> “Mail” (at left pane) >>Under “Compose messages” section (at right pane) >> Click on “Stationery and Fonts” button.
3. Under “Personal Stationery” Tab move on “New mail messages” section and click on “Font” Button.
4. A new window will appear, Under the Font Tab, you can select any font that you want.
5.Click “Ok”.
Font Style for reply to or forward:
Follow all the above given steps, except step 3. Because that particular step has been already chosen in earlier font style of “New Mail Message”. Now, choose “Replying or forwarding messages” and start doing changes.