Here’s a simple comment:

// Hello, world!

In Motoko, comments must start with two slashes and continue until the end of the line. For comments that extend beyond a single line, you’ll need to include // on each line, like this:

// Hello, world! I have a lot to say, so much that it will take multiple// lines of text. Therefore, I will start each line with // to denote it// as part of a multi-line comment.

Comments can also be placed at the end of lines containing code:

func add(x : Nat, y :  Nat) : Nat {  x + y // here we are adding two values together};add(2,3);

func multiply(x : Nat, y : Nat) : Nat {  // here we are multiplying x by y  x * y};multiply(2, 3);