Studying in the United States is not a direct path to permanent residence, but a student visa is easier to obtain than many others. And while you are in the United States in your course of study, you will have the opportunity to interact with people in your chosen industry.
Establishing those connections can be very helpful in getting you the job offer you need to live there permanently, because someone who has a personal relationship with you is much more likely to go through the hoops necessary to support your application for permanent residence.
To get a student visa to the U.S., you must first be accepted into an approved program. Acceptance will activate your enrollment in the Student and Exchange Visitor Information System, for which you must pay a fee. After doing so, your school will give you an I-20 form that can be used to apply for a student visa.
Your visa will be an F-1, for most academic institutions, or an M-1 for vocational training. Students between the ages of 14 and 79 will probably have to attend a face-to-face meeting with a U.S. embassy official in their own country during the process.
If they are married or have minor children, they will need their own visas, either F-2 or M-2. Children are allowed to attend school in the United States for as long as they reside there with you. Please note that citizens of Canada and Bermuda do not need visas to enter the United States as students, but they do need an I-20 from their school.