As international student, you can request for an official letter from the registrar confirming your enrolment with the school. That is if your school does that. Some school make this available on the website or portal. After this, you will write a letter of invitation, stating when, why, where they will be staying/accommodation arrangement. Who will be responsible for their living expenses while in Canada. And many more reasons. Just like a citizen or PR holder will do. You will attach clear copy of your valid study permit to be submitted along with the application. It is better to go for family visitor in their case than tourism. The chances is high. Especially, if they are the one responsible for your finance in Canada.
