[list=1][*]Select the range of cells that you want to format with commas.[*]Press the keys "Ctrl + 1" on your keyboard. This will open the "Format Cells" dialog box.[*]In the "Number" tab, select "Number" as the category.[*]In the "Decimal Places" field, enter "0" (zero) if you want to display whole numbers with commas or enter the desired number of decimal places.[*]Click on the "Use 1000 Separator (,) " checkbox to enable it.[*]Click on the "OK" button to apply the changes.

Alternatively, you can use the shortcut key "Ctrl + Shift + 1" to apply the comma format directly to the selected range without opening the "Format Cells" dialog box. This shortcut key works for both Windows and Mac versions of Excel.