You can use: привет - privet - "hi" for your friends (agemates), parents здравствуй - zdrastvuj - "hi" for little children or said by old people здравствуйте - zdrastvujte - "hi" for old people, official --- здорово - zdarova - "hi" using with old friends, if the comisng is unexpected, etc. хай - haj - barbarism from Englsih popular with youth

Привет (privet) - hi, hello , Здравствуйте - zsravstvuyte also.