Buddhism is a religion that teaches people to be kind and avoid doing harmful things. Capital punishment means when somebody gets killed by the government when they have done a very bad thing.
Buddhism generally teaches that hurting or killing another person is wrong, even if that person did something very bad. People who follow Buddhism believe that everyone has the potential to change and be better. They also believe in something called karma, which means that everything a person does will have consequences, either good or bad. They think that if somebody does something really bad, then they will suffer for it in the future, either in this life or the next.
Many Buddhists believe in finding ways to help people who have done bad things to understand what they did wrong, make amends, and change their behavior. They also believe that forgiveness is important, and that executing somebody doesn't allow for forgiveness or change. So, generally speaking, Buddhists are against the death penalty.
Of course, not all Buddhists think exactly the same way, and there are some situations where some people might believe that executing somebody was the right choice. But overall, the general idea is that killing people is not the right way to address problems, and that we should try to find better solutions that allow people to grow and change.