Printer

Click on this link to the HP Support page for your printer,

https://support.hp.com/us-en/drivers/selfservice/hp-officejet-pro-6970-all-in-one-printer-series/8289585/model/11161258

Make sure the operating selector is set to macOS 10.14 Mojave,

Click on the + boxes to reveal the downloads available to you,

there is a critical firmware update, download and then install this update.

Download and run the HP Smart app, this should allow you to download the necessary

drivers and software for your mac.

The HP Easy Start app does much the same, so choose which one you want to use.

It may also be necessary to reset the printing system,

Reset the Mac printing system to solve a problem - Apple Support

HP alleges that printer is Apple AirPrint-enabled: HP Printers - Mobile Printing Solutions Compatible with HP Printers.

Open  (Apple menu) > System Preferences... > Printers & Scanners and remove the existing printer. Then add it again, this time being sure to explicitly select AirPrint. Refer to About AirPrint - Apple Support.

Do not install any drivers from HP. They won't work.