I have a 6-year-old kid. How can I teach him about communicating and sharing things with us so that we can help him out?

The first thing that parents do wrong is they never listen to the full story, and start scolding them. As a result, he/she starts hiding things and stops communicating because he/she knows that he is going to be scolded again. Since the maturity level of a 6-year kid is very low, scolding them for their mistakes only makes them scared of you. Hence, communicate with them, listen to what they have to say, understand his/her mentality and make them aware of what is right and what is wrong. Once you start listening and communicating with them, they will definitely come and share all the right/wrongdoings.