HTML newsletter design is not a feature that Microsoft's Outlook e-mail application was built for. However, that doesn't mean it's impossible to pull off. You can create a simple HTML e-mail using Outlook's WYSIWYG editor and send it to a distribution list.
Open the Microsoft Outlook application from the Start menu.
Click "File" in the menu bar, hover over the "New" option, then select "Distribution List."
Add your newsletter's recipients to the distribution list by clicking the "Add New" button and filling out the subscriber's name and e-mail address. Save and close the distribution list.
Create a new HTML e-mail and design it to your liking. By clicking the "Insert" tab, you can add many HTML objects to your e-mail, such as pictures, tables and hyperlinks.
Click the "To" button and select the distribution list you created back in Step 3.
Open the "File" menu, select "Save As" and save your e-mail as a Microsoft Outlook template. The next time you want to send a newsletter, you can now open your template instead of creating a newsletter from scratch.
Click "Send" to send your HTML newsletter.