You can change the date & time format in Google Sheets & Excel Online using this guide. Use different date & time formats in spreadsheets.

Before doing anything with the subtotals, you must remember to apply the Visible Cells Only option. If you forget, Excel will apply the format to all of the data cells as well.

How to add a conditional format that highlights groups in Excel Your email has been sent The article, How to use a border to discern groups more easily in Microsoft Excel, shows you how to use a ...