Windows: use the Character Map, Word’s superscript button, or the keyboard shortcut Ctrl+Shift+=
Mac: use the superscript formatting option in your app, or the shortcut Command+Shift+Plus
Google Docs: select text, then Format > Text > Superscript, or use Ctrl+.
Microsoft Word: select text, then click the superscript button or press Ctrl+Shift+=
HTML: use the `` tag
LaTeX: use `^` in math mode
Plain text: use Unicode superscript characters when available
Mobile devices: use the text formatting menu in the keyboard or app toolbar