Depending upon the category of Canadian Immigration, you should submit the support documents.
For applying in Skilled Worker category, you should submit a copy of your passport bio-data page, and the correct Canadian government processing fees, which should be paid in favor of the Receiver General for Canada.
A copy of your work permit along with a letter from your employer citing that till receiving your Canadian Immigration visa, you will be employed for an indeterminate period should be stated. Human Resource and Social Development Canada issues an arranged employment opinion letter after receiving your permanent job offer letter from your employee. So you have to submit a photocopy of Arranged Employment Opinion letter or copy of work permit if you are applying under work permit or arranged employment category.
International students in Canada must submit their study permit or any other proofs relating to their student status. Under some circumstances additional documents can also be asked by the Canadian Immigration office.
Evidences of genuine relationship between the two parties, any proofs regarding the civil status, and guarantee for the ability to provide support must be submitted when you are applying under Family Relationship category.
Documents for the presence of sufficient amount of assets, civil status, and business management/ownership experience should be submitted when applying under the Business category of Canadian immigration.
If you want to live in the province of Quebec or if you are eager to reside in any specific province then you have to submit documents regarding the province’s requirements, if you are applying in the Provincial nomination Program of Canadian Immigration.
Proofs for your post-secondary studies or for your work experience must be submitted as supporting documents when you are applying under Canadian Experience Class category.
The most fundamental document which you compulsorily need is a police clearance certificate obtained from all the countries where you have resided for a period more than 6 months since your 18th birthday.
But under certain situations the Canadian Immigration Office may ask for any additional documents, so you are advised to seek expert’s advice.