Setup a Default Printer in Windows 10

1. Select the Start button and then Settings 
2. Go to Devices > Printers & scanners > select a printer > Manage. 
3.  Then select Set as default.  If you have Let Windows manage my default printer selected, you'll need to deselect it before you can choose a default printer on your own.

In Windows 10, your default can be the printer you last used. To turn on this mode, open Start  and select Settings  > Devices > Printers & scanners. Select the checkbox beside Let Windows manage my default printer.