Generally there is no visa requirement to start a company. Anyone can file for and incorporate a startup in the US. Where you run into problems is that you can’t actually work for your company in the US unless you have a valid working visa. As some of the other answers point out, you can apply for a few different types of visas depending on the specifics of your situation. Each type has different qualifications and purposes so first you need to decide which visa applies to you.
If you have experience running businesses successfully, you may qualify for an O-1 visa. The 0-1 visa is for “individuals with extraordinary ability.” These are usually used by athletes or performers, but business is a qualifying category. So, if you can show that you have extraordinary ability running a business, you may qualify for an 0-1. You would then be able to run your startup in the US. This would probably be the least complicated process, but there are other ways if you don’t qualify.
An H1B visa is another option that would let you work for your company, but you would need an employer to sponsor you, meaning you would need to be an employee of your company and own less than 50%. This may be a good option if you can raise your salary in exchange for less equity. Or, if you already own less than 50%. The problem here is that the employer relationship requirement may not be ideal in some situations. On the other hand, it may not be a big deal in other situations. For example, you could still be the CEO and have significant control if you simply have a board of directors right above you.
Also consider an E-2 visa. This nonimmigrant visa allows a non-U.S. citizen who controls a substantial investment to work inside the country. The U.S. Citizenship and Immigration Services (USCIS) requires an E-2 visa applicant to submit extensive documentation to prove their investment in a bona fide enterprise. To be eligible for an E-2 investor visa, the applicant must be from a treaty investor country that has reciprocity with the U.S. A minimum investment of $100,000 is initially required.
Other options exist and you should really take a more detailed look to decide what option would work best for you. For that reason, I suggest that you talk to an immigration lawyer. An experienced immigration lawyer will be able to talk to you about your best options and walk you through the process. If you are looking for help with an immigration matter, you should visitwhere we will match you with an experienced attorney for a free consultation. Hope this helps.