It's not 90 days extension. It's an in-country Non-O VISA based on retirement/being over 50. Those are different.
You NEED to go to your local immigration office to get the latest requirements handout. Those are immigration offices specific. There is no one-fit-to-all list. And those could be updated anytime.
Here is the General information, but this is NOT the same as the one from any of the provinces.
*********************************************************************************************************
*******
/9.FOR-RETIREMENT-PURPOSES-50-YEARS-OLD-NON-O.pdf