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.
Moreover, you can also use Word templates for letterheads, invoices and even for monthly business reports. This is because it is integrated with other Microsoft Office programs such as excel. This way, you can import graphs and other objects necessary for completing a well formatted report. There really is a long list of uses for Microsoft Word. You will certainly find it useful whether you are a student, a professor, a businessman, a home maker or whoever you are from whatever industry.