In my salary/saving account can i take money from other country till $4.00 Millennium, what is necessary for ?

I am reading a book releted to that so i have dought about that if anyone from outof country transefering his amont till $4.00 millennium on my account, is it possibal ? i am from middle cl family, will it be problemetic for govrnmrnt ? how ? what will be action of that people ? then what kind of process that person ( example me) have to do ?