After they are married, he will have to sponsor her for permanent residency through the Family Sponsorship program. He will need to be living in Canada when he submits the sponsorship application and will have to continue living in Canada while the application is processed. She can try applying for a TRV to join him in Canada as a visitor while they wait for the application processing to be completed. However there is a good chance the TRV will be refused and she will need to remain in Pakistan and live separately from him until her PR visa is approved.
