You can file your own incorporation papers with the SEC of your state. That is not the most straightforward path.
The easiest thing to do is to hire a corporate attorney to do it for you. There are many lawyers in the Boston area with startup practices that can help you with this task.
This article builds on content developed by the Martin Trust Center for MIT Entrepreneurship for MIT's Orbit Knowledgebase and is licensed under CC BY-NC-SA 4.0.