Printing options iPhone 12 Pro max
I try to print from my iPhone 12 Pro Max and there is no option to print in letter size
iPhone 12 Pro Max, iOS 17
The options provided are down to the printer being used. Whatever it exposes tom the print dialog is what you get.
Apple has no control over what features and paper sizes the AirPrint printers offer to the print dialog.
From the standard options, 8x10 is the closest one to Letter size (8.5x11).