1. Put "Mon" without quotes in a Cell. Let's assume this is in cell A1 here. If you want to generate full names of the day, put "Monday" without quotes.
Note – The start day can be any WORK day. "Mon" is chosen for illustration purpose only. The start day will be whatever is put in cell A1.
2. Drag the bottom left corner till row 5 (or to any number of rows) by pressing right click.
3. Leave Right Click.
4. From the menu which pops up, select Fill Weekdays. It will populate all cells with workdays of the week except Sat and Sun i.e. with only Workdays.