I installed a new printer Canon MF624CW when I go to print an email from Gmail app and click print it keeps coming up with the original HP printer app and will not let me switch to the New Canon print app
Install Cloud Print. Uninstall the HP Printer app. Set Cloud Print up to print from the printers you want to print from. If there's only 1, that's where you'll print. (You "share" the email with Cloud Print, which prints it.) If there's more than one printer set up, you'll get a choice of printers to print from.