Comments in code are unexecuted lines of code that are not run by the computer, and can be used to add additional information or guidance within the code. You can use comments to explain a complex algorithm, add reminders of things to do later, or just explain code for documentation. This would be like the computer reading a recipe you wrote but you’ve told them to ignore certain lines of the recipe.
Dependent on the programming language, comments are usually prefixed or wrapped in certain syntax to ensure the computer knows that they’re comments and are not to be executed.
// This is a comment, and won't be executed
var a = 6;
var b = 4 + a;