October 9, 2017
Google is rolling out a new feature that allows you to customize the headers and footers in your Google Sheets with whatever text you choose. In addition, you can choose from pre-defined options (date, time, etc.) and move those elements around within your header and footer. To add custom headers and footers, choose EDIT CUSTOM FIELDS from the Print settings menu to get started.
Google is also introducing saved print settings with this feature. Modify your settings once, and they will be retained the next time you—or a collaborator—opens the spreadsheet.