The subscript is commonly used to mark the contents that need more attention or explanation. Please follow steps below to subscript your contents:
Step 1: Select the contents you need to subscript;
Step 2: Right click your mouse to bring up the dialog box, from the list, click "Format Cells";
Step 3: In the "Format Cells" dialog box, check "Subscript".
Step 4: Click "OK" at the bottom.