Thank you for your information.
From the above link: only the one who is a student or has work permit can apply new visitor visa within Canada.
My mother is a visitor. Where can I find the information she could apply whitin Canada or some other office ouside Canada?
Thank you very much.
If you are currently a temporary resident in Canada with a valid status (that is, a study or work permit), you can apply for a new visitor visa to return to Canada before you leave.