Use the overline notation: write the digit with a line above it, such as x̅
In LaTeX, use `bar{n}` for a single character or `overline{123}` for multiple digits
In Microsoft Word, insert an equation and use the overbar or accent option
In plain text, use a combining overline character if supported, such as `n̅`
In HTML, use `123`
In Unicode, use combining overline `U+0305` after the number or character