DecimalForm

DecimalForm[expr] prints with approximate real numbers in expr always given in decimal form, without scientific notation.

DecimalForm[expr, n] prints with approximate real numbers given in decimal form to n-digit precision.

DecimalForm[expr, {n, f}] prints with approximate real numbers having n digits, with f digits to the right of the decimal point.

Examples

Display a number in decimal form:

DecimalForm[1.23456789*^-5, 10]
(* 0.0000123457 *)

Please visit the official Wolfram Language Reference for more details.