If you are unable to change the date format in Excel, check the cell format, you need to change the cell format. This post will help you do that.

Excel spreadsheets permit you to stay organized while managing large amounts of data, which can be organized in a number of ways. One popular way to organize this data is by date. Excel has a default ...

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