This is nothing different from a document file, but you can work on it to publish on web directly as a web form template. This one is the latest feature of word. You have several integrated programs to improvise your templates in terms of visual appearance. You also have the option to work with the add_ons in MS word. If you work wisely, you can bring out a professional template all by yourself.
Personally I like to place my business address at the bottom of the page or the footer. To do this go to the floating bar and click on the button, 'Switch Between Header and Footer.' This will open a dotted box at the bottom of the document. You can type your office address here or anything you see fit for your letterhead. Again you can format the text by choosing the font, font size, color, align the text, etc.