It looks like you're using Internet Explorer 11 or older. This website works best with modern browsers such as the latest versions of Chrome, Firefox, Safari, and Edge. If you continue with this browser, you may see unexpected results.
Investopedia is an ad-driven publicly available website focused on investing. It includes a Financial Terms Dictionary. Definitions of SEC forms are provided. Search on the name of the general category, such as "SEC Form D" rather than "SEC D(06b)".