She applies for a visitor visa but if she is a refugee then getting one will be very difficult. She needs to show funds, strong ties to home country and travel history. Is she registered with UNHRC? The issue will be that IRCC will know she will claim refugee status once she comes to Canada.
Her only option at this time is to apply for a TRV.
Unfortunately chances are extremely high the TRV will be refused and she will not be allowed to visit due to her refugee status.
If you meet the income requirements, I would recommend that you look into entering the parent / grandparent sponsorship program lottery next year. This is probably the most realistic way that you will eventually be able to bring your mother to Canada.
Then a visitor visa will be extremely difficult because she has to prove that she will return to her home country with funds to support her visit. If she has refugee status, she will claim once in Canada. Look at sponsoring through PGP if you and your spouse are PR and meet LICO for the past 3 years.
