Are you US citizen/Resident ? Are you working in Canada and living there or you work in the USA and your spouse intends to join you during 2019? Is she a Canadian citizen ? If you plan to live in Canada ( settle down there for the foreseeable future ) , then also say that.
If you are in the USA, a US citizen, it would be best for you to visit the nearest consulate to understand the ramifications and things that you have to do for a smooth married life ( as far as immigration is concerned ). For getting ITIN ( required for filing Married Filing Jointly ) , you need to download W-7 from the IRS site -- www.irs.gov -- it will provide all the information on the process.
Please answer my questions -- then perhaps I can provide more specific answers.
