VS代表哪种签证种类？
Visa 即护照上的签证，由入境国发给准备前往该国的人员的一种纸制凭证。 持有Visa 者可以取得入境许可、进行短期旅行；但不同国家或地区对于是否允许持有Visa 人进入其国内及是否允许多次进出有其规定，有些国家对持用Visa 有特别限制甚至拒绝给与Visa， 而且Visa 的有效期和次数也是有限制，所以申请人必须注意申请Visa 时必须符合该国的条件。而各国发放Visa 种类繁多，有的只有1个不同的种类，有的多达上百种;且同一种类的Visa 可再细分为数种小种类(sub-category)，例如：B2 又可分为B2/NFTL 和 B2/MULTl.。
美国移民法规定，凡申请赴美定居的外国人（即“移民”）应获得移民签证 (Immigrant Visa); 而凡赴美观光、探亲访友或短期观光者（即非移民）则需获得非移民签证 (Non Immigrant Visa)。因此， VISA 在美國分為兩種： 移民簽證 (Immigrant Visa)， 給留美的永久居民與公民; 非移民簽證， 是給來美觀光、探亲、訪問學、工作等等之海外人士。
目前中國人最常申請的就是以下的幾種Visa： F-1学生签 F-1 Student 学生簽證是給留学生的簽證，一般以短期留学为主，通常需要50-60美元的费用，如果申请人被学校录取后，在去移民局面试之前，学校通常会收到一张I-20表格以及一封通知申请人面谈的通知信。 一旦申请人拿到Visa，通常上面都会注明「F-1 STUDENT」 另外，如果申请人想要转學或是休學時間超過1年，都需要向移民局提出「Change of Status」，以免超期停留而被遣送出境。 M-1 非移民簽證，給短期的專業訓練學生的簽證。此簽證不適用於博士生。
J-1交换學生簽證 J-1 is the visa for foreign students who participate in an exchange program， commonly known as "exchange visitors" or "foreign trainees，" sponsored by U.S. government agencies and private non-profit organizations. The primary purpose of these programs are to provide practical training， employment experience and professional development opportunities that can be applied toward a career back home. This includes medical professionals， researchers and scholars at all levels， business people (including executives)， teachers working temporarily abroad under the Teachers Exchange Program， cultural exchange participants such as summer camp counselors， and interns of other types.
The main advantage of this visa over student visas is that it does not restrict work rights. Therefore， international students on a study program may use their J-1 visa to get part time jobs without having to apply for another type of visa first， provided they meet certain requirements including maintaining full-time enrollment status and receiving permission from the US Department of State. If you will have any questions about your eligibility please contact us. 另外要注意的是，J-1 holders can't change their visa status once it expires. However， if you leave the United States for more than one year， you must reapply through the consular process with a new visa.