A person who seeks an immigration visa, the applicant must have knowledge about US immigration laws. If after filing case, even the alien says: "I don't know about these laws, No uses".
Given the brief information may help to know fundamental Immigration laws.

Immigration and Nationality Act (INA) can tie-up with rights, duties and responsibilities of the foreigners in the USA.

The petitioner who is seeking to enter the USA for business or live may require a Visa. If the purpose is short period its Non-immigration Visa, long time-period it's under Immigration Visa category. The entire Immigrant visas responsibility of the U.S. Citizenship and Immigration Services (USCIS).

Over the past five years, the U.S immigration laws have become much more strict rules after the WTC tragedy. Application fees and other tax fees also increase. Almost without a good US Immigration lawyer's help it’s too risk and complicated to get any US Visa.

Immigrant refers a person who is interested stay in the other country is called Immigrant.
If you don't have visa, you can go to the USA without any visa under the Visa waiver program (VWP).
You must do anything under immigration laws only.
If you go to the USA for studying purposes, you are not starting any business.
If you do business it's punishable offense, but you can extend the previous visa.
If you are interested to stay permanently in the United States, apply Green card.

You can eligible to enter into your motherland any time and come back to the USA as you wish. But some conditions the visa is cancelled: for example: you having H1B visa, you come back to your motherland (India). You have lost your job when you are in India, now you are not eligible to go to the United States due to you are not qualified H1B visa.

If you have dependents they are also eligible to enter the USA with the help of H4 visas.

Almost all visas having maximum visas count. If the visa applicants crossed that maximum count, you are not eligible to get a visa until next year. Most of the people waiting for H1B visas up to the April first week of the every year.
In the USA, many Immigration law firms available choose American Immigration Lawyers Association (AILA) lawyers if you face any legal problems.
The alien must submit their financial funds status during the interview process; otherwise you face a lot of financial problems.
Highly recommend taking Health insurance temporary period. Health insurance companies offering different health plans in the USA. In the USA medical charges are too expensive, so you must apply good health insurance plan.
Almost all products and services can book through online. Many religious organizations are in different places. You can approach them if you need any help.
Depends on your behaviour, Immigration offers can possible to reject your visa.
If you lost your visa, apply Form I-94 form and inform to the Department of Homeland Security (DHS).
Any time you don’t take local consultancy; always contact your family lawyer or Immigration Lawyer only.

Author's Bio: 

I am Venu.k I like to share my knowledge through online. I have knowledge knowledge how to apply Green card so that i shared my knowledge. I hope it may helps to you. New York Immigration Lawyer Naresh Gehi shared his knowledge with me. Similarly i am gaining knowledge on Internet marketing and health related information. If you interested tell me. Thanks