Do

Do[expr, n] evaluates expr n times.

Do[expr, {i, imax}] evaluates expr with the variable i successively taking on the values 1 through imax.

Do[expr, {i, imin, imax}] starts with i=imin.

Do[expr, {i, imin, imax, di}] uses steps di.

Examples

Print numbers 1 through 5:

Do[Print[i], {i, 5}]
(* Prints 1, 2, 3, 4, 5 *)

Nested iteration:

Do[Print[{i, j}], {i, 2}, {j, 2}]
(* Prints {1,1}, {1,2}, {2,1}, {2,2} *)

Please visit the official Wolfram Language Reference for more details.