You can add a zero before a number in Google Sheets and Excel using this tutorial. You need to change cell formatting or use function.

Here are the multiple methods using which you can keep the leading zeros that are automatically omitted before a number in an Excel workbook.

How to Enter a Subscript in Excel. Properly formatting expressions such as "H2O" in your Excel spreadsheet requires the use of subscripts. Subscript formatting makes a letter or number appear ...