Q: how to use AirPrint with Iphone 6

That printer doesn't support AirPrint - those that do are listed on this page : About AirPrint.

You could see if Canon have their own app in your country's app store that supports that model, or there are third-party printer apps such as PrintCentral Pro and Print n Share which might work with it.

(For info you've posted in the Using iPad forum.)

Canon MG7520 most definitely supports AirPrint. It's in the printer docs and I use it regularly. The only reason it's not listed on that page is because it's too new.

Try installing the latest update from http://www.usa.canon.com/cusa/consumer/products/printers_multifunction/photo_all _in_one_inkjet_printers/pixma_mg7520?selectedName=DriversAndSoftware . Looks like a new one was posted just a few days ago.