To choose a default printer, select the Start button and then Settings . Go to Devices > Printers & scanners > select a printer > Manage. 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.