The government of US provided an array of visas for immigrants and non-immigrant students. Purpose of your visa to US determines the type of visa you need. For instance, if you're on a temporary visit then, it can be tourist visa, business visa, student visa, etc. however, if you're planning to settle in US permanently, then you will need green card or an immigrant visa.

Here are some of the steps to obtain US visa:
Obtain the necessary application form from the US embassy and consulate.
Once you have filled your form submit them with in the embassy or consulate along with all the essential documents such as passport, papers regarding your employment, reason for travel, and financial status. You'll also be required to deposit certain fee amount along with the application.
Within a few weeks the submitted application is reviewed either by the consular officer. However, if your form indicates any security concerns, the process get delayed.
Finally, you may be called for interviews to provide additional information or fingerprinting.

The visa of an applicants is also processed on the basis of the type of visa and the circumstances in the country you belong. Hence, it's better to first contact the embassy or the consulate about the regularities before applying for visa.

As per the 2007 report, more than 5.5 million people applied for green cards out of which only 82,000 applicants were approved for immigrant visa. So, if you're planning for an international education visa it would be better to go through these steps before applying.