This brief overview of the XLTools Popup Calendar add-in (a datepicker for Excel) shows:
How the Calendar displays weekdays, week numbers, and today’s date
How to quickly enter and edit dates in cells, columns, rows, ranges or merged cells
How to change date format settings, and more
Download at https://xltools.net/download/
Suitable for Microsoft Excel 2016, 2013, 2010, 2007, and desktop version of Office 365 (32-bit and 64-bit).