There is no special category for spousal visitor visa. She has to apply for the same visitor visa anyone else would. To be approved, she has to show ties to India so that the visa officer will believe she will leave Canada before the visa expires. With a spouse in Canada, this can be difficult to do, but some people have received them even though they have applied for PR.
If she has a job, she can get a letter from her employer proving she has a job and giving her a few weeks off. Other ties are things like a mortgage or lease or home ownership, money in the bank, investments, children left behind, family ties, etc. A return ticket with a specific date is a good idea as well.