Select the text you want to make subscript
Press Ctrl+= on Windows
Press Command+= on Mac
Click the Subscript button in the Font group on the Home tab
Open the Font dialog box and check Subscript
Use the keyboard shortcut again to turn subscript off
Select the text you want to make subscript
Press Ctrl+= on Windows
Press Command+= on Mac
Click the Subscript button in the Font group on the Home tab
Open the Font dialog box and check Subscript
Use the keyboard shortcut again to turn subscript off