How many kinds of visas are there for going to America? What are the uses?

According to American immigration law, American visas are classified into 18 categories, and there are 48 categories in alphabetical order. From A to R, the student visa is generally F 1 visa \x0d\ This 18 category is: \ x0d \ A- diplomat \ x0d \ B- short-term visitor \ E- special investor \ x0d \ F- student \ x0d \ G- international organization personnel. Class n —— representatives of member countries of the North Atlantic Organization and their families, families of special immigrants \x0d\O —— outstanding people and assistants \x0d\P —— international celebrities and their families \x0d\Q —— cultural exchange project personnel \ x0d \ R———— religious people.