美国h签证是什么签证？
1，H签是移民签证的一种，即非移民签证的其中一种.
2，一般申请到H-1B的人都需要有美国的雇主提供工作合同和薪资证明才能成功获得此签证。
3，H1 B visa allows a foreign worker to come and work in the USA for a specified period of time， generally three years with possibility of extension up to six years total duration （65个months） ， but this is subject to change according to the government policies from time to time; it also does not lead to permanent residency unless you are already working under an employment based immigrant petition (Green Card) filed by your current employer or another one waiting in the “line” for the priority date， which usually takes many years. The H1b holder can only be employed by the sponsoring company he/she was assigned to， hence the name "employer sponsored". This means that if the employee chooses to switch jobs within the same industry(eg.from A corporation to its competitor， XYZ Inc)， then a new visa application would have to go through. However， this is allowed easily once every year provided there's no lapse between the last day of previous job and first day of new job; however， switching employers outside the same industry requires labor certification plus approval from the USCIS. Since these immigration processes could take several more years even after getting green card， some workers choose to live illegally in US rather than risking losing their status as legal residents； others opt out at early stage without pursuing citizenship due to concerns about future changes in policy. There were cases where people had been on H1B for over two decades before finally obtaining Green Cards， while other got deported back home because they took part-time jobs instead of full-time work stipulated by their contracts， etc. It all depends on individual circumstances and choices made along the way. Many immigrants find themselves stuck between a rock and hard place --- too much money has gone into acquiring the necessary licenses needed for practicing profession here， yet they cannot bring family members here legally and have to face uncertain immigration procedures should they decide to pursue Citizenship after years of working hard towards career advancement and accumulation of wealth and assets here，