Non-voting means choosing not to participate in an election by not casting your vote. When we have an election, we ask people to choose their favorite candidate, just like choosing your favorite toy or candy. Voting is like telling everyone which toy or candy you like the most. Non-voting means you don't say anything, like when you don't want to tell your parents which candy you like the most.
People may choose not to vote for many reasons. They may be busy with other things, they may not care about the election, or they may not like any of the candidates. Sometimes people don't vote because they don't think their vote will make a difference, but it's important to remember that every vote counts and can make a difference.