For user registration I have created User Form. I want to add two drop down(Province and City). I want to populate data automatically. Default Country is "Canada". So Province and City should be populate automatically.
You can create taxonomies or custom fields for province and city, but you need to set the options up yourself.
There is a filter—wpt_field_options—that can be used to dynamically populate a custom field select dropdown, but you need to provide the values and display values in the required JSON format, so you would still need to provide the values from somewhere.
Alternatively you could add a Maps address field where the user enters either a full address or a partial address, such as Toronto, Ontario, chosen from the Google autocomplete.
The formatted address would be stored as a text field.
Google returns more than just the formatted text field, but we don't use anything else apart from the lat/lon coordinates, though it is possible to add some custom JS to extract different parts of the address for your own use.