My canon printer will no longer connect to my Mac. How do I update it to do 64 bit?

You most likely cannot update a 32-bit app on an 11 year old device. At 11 years old, you will need to look for a new printer or continue to use an old OS version. Check with Canon - my guess is that they will no longer support an 11 year old printer. Here is some info from Apple:

32-bit app compatibility with macOS High Sierra 10.13.4 and later - Apple Support

You'd have to ask Canon if your printer is capable of being updated.