It depends on the laws of the country where you live. In most countries, they require background check in order to issue a visa no matter what the purpose is.
How to get a visa depends on what type of visa you wish to acquire: Family Visas Student Visas Work Visas Visitor Visas Getting a visa from any country usually requires filling-up a visa application...
The visa is a sticker that has been put in your passport. The number is, I think, the number that's printed vertically on the right.
The only other numbers on the visa are the two lines along the...