My case was different so I won't attempt to say exactly what applies to yours.Yes, thank you , I ll definitely read. So I shall not send all the work history docs, if you can please provide a hint. I am only sponsoring my spouse
In general each applicant needs to demonstrate they can support their spouse financially. For those in Canada for years this would include tax returns, your situation will be different. If you're a recent arrival savings and plans to work (update during process once you find work).
You may want to show evidence of your professional qualifications and work history as evidence of your ability to support your spouse, but 'proof' implies a higher level of documentation than may be needed or required. And of course you probably already showed your education and work history with more extensive proof when you immigrated yourself.
But again: start with the instructions.