Win 7 Home - Custom Theme for Outlook

Hello FDigital01, welcome to the forum.

I think this is what you are look for:
Apply stationery or backgrounds to e-mail messages - Outlook - Office.com

Example:

Apply Outlook stationery and themes to all messages

Note This procedure works only if you use HTML as your message format.

1. From the main Outlook window, on the Tools menu, click Options, and then click the Mail Format tab.
2. In the Compose in this message format list, click HTML.
3. Click Stationery and Fonts.
4. On the Personal Stationery tab, click Theme.
5. Under Choose a theme, click the theme or stationery that you want, and then click OK.

1. Select the font options that you want to use.
2. If you want comments that you type in message replies to be labeled with your name, select the Mark my comments with check box and type a label, such as your name.
3. If you want your font to appear in a different color each time you reply to or forward a message, select the Pick a new color when replying or forwarding check box.
4. Click OK twice.

When you create new messages, they will automatically use the stationery or theme that you chose.
Tip To choose Outlook stationery or themes from an open message, on the Insert tab, in the Include group, click Signature, and then click Signatures. Click the Personal Stationery tab, and then click Theme.
Note Outlook stationery or themes cannot be customized.

Outlook is part of the Office Suite not your Operating System, Windows 7.

You should be able to create a template by using the example which I used or perhaps Word. It would be beneficial for you to read the options available in my link. :)