If you run into a conditional header or footer request that you can't handle, take a look at Word fields. They're not magic, but it kind of feels like magic when they do what you want.

Insert a Footer in Excel If you want to add a footer to an Excel spreadsheet, click the "Insert" tab on the ribbon menu. Then click "Header & Footer" within the "Text" group of options.

You can insert or add Header and Footer in Excel spreadsheet using this tutorial. Insert page number, current date and time, etc.