In many versions of Excel, you can use a Microsoft date picker control to create an Excel date drop-down in a cell. Unfortunately, this won't work in 64-bit versions of the popular spreadsheet ...

If your cells contain data, the sample displays the first date in your range of selected cells. Click "OK" to apply your formatting. Press "Ctrl-C" to copy the cells you formatted.

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.

Microsoft Word has a date field, but it's not easy to use in an expression. If you need to update dates in a document, use Excel to calculate the dates and then run a mail merge.