You have to go back in person to renew both! For your health card, if it's the new one (green with photo), then you definitely do. If you have the old OHIP (red and white), since there's no expiration date, you don't have to renew it. For driver's license, I think If you return to Canada within 2/3 years (plse double check) after it expires, you can still renew it without going through written and driving test.
for the new health card - u need to take photo every time you renew it...
for the driver licence, if you renew it within 3 yrs - no driving test is required - or else, you will have to gone thru all the stage again from scratch.