hello = Namastey! how are you? = aap kaise hai? / aap kaisi hai? / Tum kaise ho? / Tum kaisi ho? bye! = Alvida !

hello = नमस्ते ! Namastey! how are you? = आप कैसे हैं? aap kaise hai? आप कैसी हैं? aap kaisi hai? तुम कैसे हो? Tum kaise ho? तुम कैसी हो? Tum kaisi ho? bye! = अलविदा। ! Alvida !

Neha you would say, 'Namaste' (for Hello), "aap(You) kesse(How) hai(are)", "Namaskar(Bye)" in hindi. I am Rocky from india aand i am learning english.