Children often lie. When they lie, it is usually for the same reason: to avoid the possible negative consequences of their actions. Perhaps these negative consequences are: the anger of their parents, the yelling, a punishment, the disappointment that parents may feel for something they have done, etc. So in the vast majority of circumstances, when a child lies, they do so out of fear and to protect themselves.
If you have a strong relationship with your children where they feel unconditionally loved and know that you are there to help them find solutions together, they will be less likely to lie to you. Acknowledge your choice to tell the truth, even if it was difficult to do, it helps reinforce the behavior you are trying to develop.
This means that you have to set a good example for your children when it comes to truth or lies. You have to show them that you are telling the truth even if the consequences that will come later are not what you would like to happen. Then, you will have to tell him what happened, taking into account his age and his understanding why you have told the truth. It is necessary to focus on building closeness and good communication with your children so that you create great trust and prevent children from lying. If children trust their parents and know that they are rational and balanced people who control their intense emotions, then they will tell the truth.
Parents of young children can read books with them that emphasize the importance of honesty, as well as talk with them about how much they value honesty and how it helps the family. The child should never be labeled a liar. Calling a child a liar can reinforce the behavior, make them believe they are a liar, and have no reason to stop lying even if you don't have the need to.