Hi, I got my ITA and I am in the process of submitting my documents. I figured I’d post the basic list of documents which CIC asks for. You might need different documents from these based on what you have filled in your EE profile. This list shows up for me when I try to submit my ITA application. Hopefully this will help you in gathering your documents well in advance. 
1. Document: Marriage License/Certificate
If you were married in Canada:
You must have a marriage certificate issued by the province or territory where the marriage took place.
If you were married outside Canada:
The marriage must be valid under the law of the country where it took place and under Canadian law.
A marriage performed in an embassy or consulate must comply with the law of the host country where it took place, not the country of nationality of the embassy or consulate.
2. Document: Passports/Travel Documents (Multiple)
You must submit a legible copy of your valid travel document which you will use to travel.
If you have a passport, you must provide a copy of:
the page that shows your birth date and country of origin, and any pages with stamps, visas or markings.
If you do not have a passport and must use another travel document, it must be issued by a government and include your:
name,
date of birth,
document number,
citizenship or residency status,
photo, and
expiry date (if applicable).
3. Document: Proof of medical exam
You require a medical exam. Learn how to get an upfront medical exam. In order to submit your online application, you will need to upload the information printout sheet or the IMM 1017B Upfront Medical Report form. Your doctor will give you one of these forms when you complete your medical exam.
If you cannot get a medical exam before the deadline to submit your work permit application, you may submit proof that you have a scheduled an appointment.
4. Document: Education (diplomas/degrees)
You must provide proof that you completed your post-secondary education. Examples of proof of education include a diploma and/or degree. Examples of post-secondary education are:
Trade/apprenticeship
Training in a specific trade, such as carpentry or auto mechanics;
Training in a profession that requires formal education but not at the university level (for example, dental technician or engineering technician); or
Training not at the university level for which a certificate/diploma is awarded.
Bachelor’s degree
This is an academic degree awarded by a college or university to those who completed an undergraduate curriculum (also called a baccalaureate). Example: a Bachelor of Arts, Science or Education.
Master’s degree
This is an academic degree awarded by a graduate school of a college or university.
Ph.D.
This is the highest university degree, usually based on at least three years of graduate studies and a thesis. Normally, you must have completed a Master’s degree before a Ph.D. can be earned.
5. Document: Employment Records
You must provide proof of work experience for your current job and for each past position you listed. Proof must include a reference letter from your employer and pay stubs, if you have them. The reference letter must:
be an official document printed on company letterhead
include your name, the company’s contact information (address, telephone number and e-mail address), the signature of your immediate
show all positions held while employed at the company
include these details: job title, duties/responsibilities, job status (if current job), the dates you worked for the company, the number of work hours per week and your annual salary plus benefits.
You must scan all documents for this period of employment and save them as one file. (You must create a separate file for each period of employment.)
6. Document: Police Certificates (Multiple)
You must provide a police certificate for every country, region or territory, other than Canada, in which you have spent 6 months or more. A police certificate is a copy of your criminal record, or a declaration of the absence of any criminal record.
Example: If you visited, worked or lived in a country for two months, left for a few years, then returned for four months, that counts as spending six months there. In this case, you would need a certificate.
Police certificates are different in each country and territory and may be called police clearance certificates, good conduct certificates, judicial record extracts, etc. They are issued by police authorities or government departments and used by Immigration, Refugees and Citizenship Canada (IRCC) to determine a person’s admissibility to enter Canada.
Certain countries will not issue a police certificate, or provide the certificate directly to you. If this applies to you please provide a letter of explanation in lieu of a police certificate.
You will be advised if you are required to obtain a police certificate for Canada.
Police certificates need to be a scan of the original police certificate(s) in color. Certified true copies, unauthorized copies, or visibly altered police certificates are unacceptable and will result in the application being rejected as incomplete.
Once you have applied for a Police Certificate from a country, it is beneficial to upload evidence that you have applied in order to ensure that your application is not rejected as incomplete (examples of proof might include payment receipts, tracking numbers, etc.)
7. Document: Proof of Means of Financial Support
Temporary Residents
If you are visiting Canada, you must prove that you can support yourself and the family members who will be with you while you are in Canada. Provide as many of these documents as you can:
your bank statements for the past four months
a bank draft in convertible currency
pay stubs
an employment letter
proof of assets or business
proof of payment of tuition and accommodation fees
tax reports, declarations or statements
proof of a student/education loan from a financial institution
a letter from the person or institution providing you with money
proof of funding paid from within Canada, if you have a scholarship or are in a Canadian-funded educational prog
proof of a Canadian bank account in your name if money has been transferred to Canada
Express Entry - Permanent Residents
If you are applying for permanent residence in Canada, you must provide an official letter issued by your financial institution indicating your financial profile. This must:
list of all your bank (chequing and savings) and investment accounts, the account numbers, dates each account was opened and the balance of each account over the past six months,
list all outstanding debts, such as credit cards and loans,
be printed on the letterhead of the financial institution, and include your name and the contact information of the financial institution (address, telephone number and e-mail address).
8. Document: Digital photo
Fe size
The final fe size of the photo must be at least 35mm x 45mm.
The photographs must show a full front view of the head and tops of shoulders, with the face in the middle of the photograph.
The size of the head, from chin to crown, must be between 31mm and 36mm.
Digital dimensions are often expressed in pixels or DPI (dots per inch). The physical dimensions in pixels must be at least 420 x 540.
Quality/resolution
If an existing photo is being scanned, the minimum resolution must be 600 pixels per inch.
File format
The file may be submitted in JPEG or JPEG2000 format.
The final size of the image should ideally be 240 kB (kilobytes), but not less than 60 kB.
The image must be in colour (24 bits per pixel) in RGB colour space, which is the common output for most digital cameras.
P.S: In our case, items 1 and 7 need to be provided only by the primary applicant (as it covers both of us). The rest of the items are required for the primary applicant as well as the spouse.
