签证，是一个主权国家的主管机关签发给外国人和本国公民允许其出入本国或居留地的许可证明，它是一个特定概念。签证本身不是证件，而是能够起法律效用的特定格式的印章和签注。签证一般做在护照上，也有少数国家使用另纸签证，但不管怎样，它必须与持证人的护照同时使用... A visa, a permit issued by a competent authority of a sovereign country to foreigners and their own citizens to allow them to enter or leave the country or place of residence, is a specific concept. The visa itself is not a document, but rather a seal and endorsement of a particular format that is legal in nature. Visa is generally done on the passport, there are a few countries using a separate visa, but in any case, it must be used with the passport holder ...