Sole Proprietor:

A sole proprietor pays income tax by reporting income or loss on his/her T1 income tax and benefit return. You have to file a T1 return if you:

Partnership:

Instead of the partnership itself paying income tax and filing a return, each partner includes a share of the partnership income or loss on a personal, corporation or trust income tax return. Each partner also has to file financial statements or any of the template forms from the CRA.

In addition to this, a partnership that carries on a business in Canada or a Canadian partnership with Canadian or foreign operations or investments must file Form T5013, Statement of Partnership Income for each of the fiscal periods of the partnership where:

    1. the partnership is a tiered partnership (has another partnership as a partner or is itself a partner in another partnership);
    2. the partnership has a corporation or a trust as a partner;
    3. the partnership invested in flow-through shares of a principal-business corporation that incurred Canadian resource expenses and renounced those expenses to the partnership; or
    4. the minister of National Revenue asked in writing for a completed Form T5013.

Corporation:

A corporation has to file a T2 corporation income tax return no later than six months after the end of every tax year, even if it does not owe tax. Financial statements and the necessary schedules must also be attached with the return.

Source: CRA, RC4070 Information for Canadian Small Businesses: http://www.cra-arc.gc.ca/E/pub/tg/rc4070/rc4070-e.html