Lawyer here, +1 David S. Roseu2019s answer. The shareholder agreement, itself, is just one of a half dozen or more documents that are interrelated and together add up to your promises that you are making to yourself, to your company, to other shareholders, and even to potential investors and, indirectly, your future customers. If you have any thought of seeking funding from investors, itu2019s critical that you talk with a business attorney before doing anything else. You can find some on platforms like Gust Launch or by contacting the bar association of your state and asking for a referral to a startup or business attorney.