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The problem is, the native printing (AirPrint) feature of iPad doesn't allow you to change settings like paper, quality etc. The settings are selected automatically based on the printing type. For emails or documents, it will select standard quality with standard paper size, for photos it will do in high quality etc.
There is an official Canon print app available for iPad named Canon PRINT Inkjet/SELPHY. This application will allow you to change paper size, quality etc. Open App Store, search and download Canon PRINT Inkjet/SELPHY
Open it and you can print using it. The problem is, it doesn't make changes to the native printing settings of iPad. This application is more limited and you cannot print all stuffs using this app.
If you have any questions or would like any additional information, please don't hesitate to ask