You can start and own a US company without a visa, and without even coming to the US. Managing an LLC from outside the US is allowed, but may be not be permitted within the US without a valid work visa. Being a director, as well as a shareholder, of a BUSINESS VISA FOR US corporation is allowed without any kind of visa, but being an officer and performing your duties within the US is generally not allowed. Working for your corporation or LLC within the US without a valid work visa is not allowed.
If you are planning to come to the US to start a business, you will need to have one of the various types of US business visas. Without a visa, you can be the owner or manager of a US company, but you cannot legally work before. If you do work for your own company without the proper visa, you can be deported without right of return, and your company can be fined for hiring an illegal alien.
The applicant maintains his or her permanent residence outside the U.S. and intends only to travel to the U.S. for a temporary stay. Proof of sufficient financial resources to allow stay in the U.S. also plays a considerable role in the examination of the application.
During the entire duration of their U.S. stay workers must remain employed outside of the U.S., preferably in the country of their principal residence. You may not receive any remuneration from a U.S. company or the U.S. branch office, and you must return to your original workplace after the completion of your stay.
Usually B-1 (business visitor) visas are granted for a period of 10 years (depending on nationality) and allow a maximum residence status in the United States of up to 180 days per entry (several times consecutively or at a time). Therefore, travelers who make frequent trips to the U.S. for business purposes do not have to constantly reapply for the visa.
Applicants must appear in person for an interview at one of the authorized U.S. consulates. In addition to the general application documents , applicants must submit documents pertaining to employment, the purpose of their entry, and other documents confirming their intention to return to their country of origin. The application is usually processed at the US VISA FOR PORTUGUESE CITIZENS consulate in the applicant’s country of residence.