I would recommend reading up on the differences between inland and outland sponsorship. If you apply for inland sponsorship, it means the principal applicant is living in Canada already. Outland sponsorship is for when the principal applicant lives outside of Canada. Because you are a PR holder, you can only be a sponsor while you live in Canada, only citizens can initiate the process from outside Canada. The principal applicant can visit Canada while the sponsorship process is ongoing, but just be warned that it can be hard to get a tourist visa. Since your partner already has one, they shouldn't have a problem. Where you get married doesn't matter, as long as you are able to get the official documentation to show that you are married. Hope that is helpful!