Freddy2147,
PR application is closed upon landing of the applicant. Therefore an applicant can withdraw his/her application, add or remove a family member at anytime before landing. PR visa contains the information that how many total members are there and how many will be moving to Canada etc. If an applicant wants to add spouse or child after issuance of PR visa but before landing, then all PR visas issued earlier must be cancelled and new PR visas must be issued to reflect the final information.
But if Principal applicants want to bring spouse to Canada as a PR after landing, then he/she will have to open new file to sponsor his/her spouse. The timeline of sponsorship is totally different and may become headache due to long delays in some cases. Obviously, until sponsorship application is successful, spouse will have to stay on visit visa as per the applicable rules.