The common method is to put the format bar in the toolbar on the first line, and there will be a font item in the drop-down menu. After selection, a dialog box will pop up, and you can choose superscript and subscript. This method is universal for both kinds of software.

Word can also select special characters when inserting an item, and it can also achieve the effect of superscript and subscript.

If you install a scientific formula plug-in in word, you can directly superscript and subscript it. The first of the three methods is the simplest.