Canon Pixma TS3420 not connecting to my iPhone 8, Macbook Air ios 10.14, or my Macbook Air 13.3

Hi,

The Canon TS3420 is listed in About AirPrint - Apple Support as a model supporting Apple's AirPrint technology, so additional apps or drivers should not be needed, provided that the printer, the iPhone and the Mac computers are connected to the same network (Wi-Fi router).

If all Wi-Fi settings are OK, and AirPrint still does not work, you could try the following procedure in this order (do not forget the router):

Power off the Wi-Fi router, the printer, the iPhone, the Macs, and all other computers/devices. Wait two to three minutes. Power on the router. Wait two to three minutes. Power on the printer. Wait a minute or two. Power on the iPhone and the Macs. Finally, power on all other computers/devices.

https://www.canon.ca/en/product?name=PIXMA_TS3420#specifications

https://www.canon.co.uk/Support/Consumer_Products/Apple_AirPrint_Guide/

Use AirPrint to print from your iPhone or iPad - Apple Support

Add a printer to your printer list so you can use it on Mac – Apple Support (UK)

Addendum

If there is a problem connecting the printer wirelessly to the Wi-Fi router, the following two support articles about WPS (Wi-Fi Protected Setup) may be of interest. WPS is an easy way of connection. There is one simple push-button method and one that uses a PIN code. Choose a method that is supported by your router (see the user's guide).

https://canoncanada.custhelp.com/app/answers/answer_view/a_id/1035565/~/connecting-printer-and-wireless-router-using-wps-push-button---ts3420-%2F-ts3425

https://canoncanada.custhelp.com/app/answers/answer_view/a_id/1035569/~/connecting-printer-and-wireless-router-using-wps-pin-code---ts3420-%2F-ts3425-%2F

It seems like that there is no driver support for this printer on High Sierra