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

It's easy to change the date format in Microsoft Excel. You just need to use the "Date" drop-down menu, which gives you plenty of options.

Here is a tutorial showing you how to change Date and Time formats (US, International, etc) on Windows 11 using Settings or Control Panel.

Open the Excel 2010 file that you want to make format changes to. Select the top-left cell in the range of cells that you want to change to the accounting format.

You can change the date format in Google Sheets and customize the appearance of calendar dates in a spreadsheet.