How can I make an investment while on a tourist visa?

You can make passive investments in any business while on a B-1 business visitor business. If you want to work or be involved in the business, you may want to look at an E-2 which works if you have the correct nationality; about 80 countries have E-treaties. If not, you can also acquire an E-2 treaty country visa via investment in that country.

As long as you don''t overstay the visa, there is no reason why you can''t invest and then go home or change to another lawful non-immigrant status while awaiting the green card.

You can make an EB-5 investment while you are in the U.S. on a tourist visa (or even from abroad if you are not in the U.S.), but merely filing for the EB-5 does not allow you remain in the United States while the case is pending. You would have to get some other visa status in order to stay here for the 2-3 years your EB-5 case is pending.

You can make an investment while on a B1 visa but you cannot work in the restaurant or engage in any type of employment/compensated work. And you will need to comply with your admission period as indicated on your I-94 or file a timely extension/change of status.

To file for an E-2 visa (Treaty Investor), you must be from a country that the United States has a treaty with for trade or commerce. Of what country are you a citizen? Also, if you filed for the EB-5, you might have immigrant intent. The E2 visa allows for dual intent of a non-immigrant who may eventually apply for immigrant status.

You can make the EB-5 investment while you are in the United States in B-1 or B-2 status, but you cannot remain in the United States unless you extend or change your non-immigrant status. A pending I-526 petition does not independently allow for any immigration benefit until it is approved, which could take 2-3 years or longer, and only if an immigrant visa number is immediately available at that time. You will need to depart the United States or change status to a non-immigrant visa status, which would allow you to remain lawfully in the United States, e.g., on F-1, E-2, H-1B. Note that a pending I-526 does not allow you to be employed in the United States or remain here while "waiting for your EB-5".