Now, you have thousands of free document templates that can be turned into web forms. What you need is, open MS word. Then you will need to go to your title bar and move to file. Here you have several existing templates to choose from. You can choose anyone among them and modify them according to your needs. Apart from changing the forms, you can start with a scrap or, blank template.
When you're done, you can click on the 'Close' tab on the floating bar. The items in the header and footer will appear greyed out, but don't worry; this only means the they have been set. The cursor will then appear on the first line where you can begin typing your letter.