Echo

Echo[expr] prints expr and returns expr.

Echo[expr, label] prints expr with a label prefix.

Echo[expr, label, f] prints f[expr] with a label and returns expr.

Examples

Print intermediate values:

Echo[2 + 2]
(* prints: 4 and returns 4 *)

With a label:

Echo[{1, 2, 3}, "value: "]
(* prints: value: {1, 2, 3} *)

Please visit the official Wolfram Language Reference for more details.