Your printer will display as "offline" if it can't communicate with your PC. Check to make sure the printer is turned on and connected to the same Wi-Fi network as your PC. To find out if your printer is connected to Wi-Fi, see if your printer's built-in menu has options for checking, or check the printer's manual for specific instructions.
If you're still having trouble printing, try uninstalling and reinstalling your printer driver. Select Start > Settings > Devices > Printers and scanners,then select the printer and select Remove Device. To reinstall it, select Start > Settings > Devices > Printers & scanners. Then select Add a printer or scanner and allow Windows to find nearby printers. Choose the one you want and select Add device.