Duplex printing on canon pixma ts3722 fromo ipad

The Canon Pixma TS3722 only supports single-sided (simplex) printing. To print on both sides of the paper, you'll need to manually flip the printed page.

https://www.usa.canon.com/shop/p/pixma-ts3722-wireless-home-all-in-one-printer

If your printer isn’t compatible wirh AirPrint feature of Apple you can’t see the printer in the option printers , you need to download the printers app and set it up from there to print from an iPad iPhone or iPod touch

You're very welcome.

Always check the device specifications prior to purchase.