Use the appropriate preposition Anita has lived in USA ________1999.

- We use "Since" after the present perfect (have been/ have done etc) 
Example: Joe is in hospital. He has been in hospital since Monday.  ( From Monday to now)

- See this picture here for more understanding , 
            Since Monday >>>>
(Monday_________________________ Now )

** We use "for" to express the meaning of period of time. i.e. Anita stayed with us for five days.  

Source: Essential Grammar in use by Raymond Murphy