Text Superscript / Subscript
From LibreOffice Help
- In the cell, select the character that you want to put in superscript or subscript.
If, for example, you want to write H20 with a subscript 2, select the 2 in the cell (not in the input line).
- Open the context menu for the selected character and choose Character. You will see the Character dialog.
- Click the Font Position tab.
- Select the Subscript option and click OK.