This list is not exhaustive, but in general, all the documents to provide us are those relating to your income, medical expenses, day care expenses, investment income, RRSP contribution, reimbursement of a HBP or LLP, income from pension, Relevé 31 issued by your landlord, student fees and more, depending on your situation.
It is also strongly recommended that you provide us with your federal and provincial notices of assessment for the previous year, as these notices sometimes contain transferable credits from year to year, which allows you to save on your taxes payable.