In apps that support formatting, select the text you want to make subscript
Press Command + = if the app uses a subscript shortcut
In Microsoft Word, press Command + = or use Format > Font > Subscript
In Google Docs, press Command + , or use Format > Text > Subscript
In Pages, press Control + Command + – or use Format > Font > Baseline > Subscript
If no shortcut works, open the app’s Format menu and choose Subscript
If the app does not support subscript, use a Unicode subscript character instead