The H1B Visa Program is the official and primary USA "work: visa / work permit.
The US Government offers the H1B visa to enable highly skilled International Workers and International Students, from all over the World, or already in the USA, the opportunity to legally live and work in America.
An H1B sponsorship employment offer is mandatory before an H1B visa can be filed. Only the US employer company (sponsor) can file the H1B visa application (not an individual / recipient).
An H1B visa is typically valid for up to six (6) years. It entitles the H1B visa holders spouse and children to 'live' in America. One of the main advantages of the H1B visa (US work permit) is that it is a 'dual intent' visa which means that you can apply for a Green Card (Legal Permanent Residency)