Morality is the concept of doing the right thing. Morals are basic guidelines for living.
Many people have written about ways of choosing what the right thing is. Some believe that there is an objective (true even if you do not agree with it) morality, often thinking it was set by God or another similar being; others think that morality is subjective (that what is good or bad is a community choice).
It can also be a lesson that someone learns in a book or story. It is usually one line at the end of the story ("The moral of this story is....."). Fables are stories with a moral.
The opposite of "moral" is "immoral", meaning the wrong thing to do. "Amoral" means something that is not related to morality, or has no morally good or bad aspect to it. It is the same as "morally neutral". Morality means that you can tell between a right and a wrong thing.
Images for kids
Allegory with a portrait of a Venetian senator (Allegory of the morality of earthly things), attributed to Tintoretto, 1585
Morality Facts for Kids. Kiddle Encyclopedia.