Question

how make good voice?

Answer 1

Scientifically, you don't 'make' a good voice. Everyone is born with a good voice, but it changes depending on how you use it.

 If you are a singer, then a regular practice of your vocals would improve it.
When you speak, speak in a low tone, not very harsh and loud. Screaming would spoil your voice.

 When eating or drinking, make sure it is either lukewarm or room-temperature. Don't eat or drink too hot or too cold things.

Salt water gargles everyday before sleeping would keep your throat clear.
 Sometimes, taking vocal naps is also good. 

 Vocal naps means staying quiet and not speaking for a while, this gives a little rest to your voice. 

Answer 2

drink some hot water daily so your throat will not be affected 
so u can make a good voice