To buy a property you need cash. Cash comes from two sources: from your own jeans, and from that of others.
Others could be:
a) bank, via a mortgage in first position (i.e. most secure, thus cheapest sub 4% these days)
b) seller, via a mortgage, frequently a second mortgage, also referred to as a VTB (Vendor Take Back mortgage)
c) joint venture partner (via RRSP, debt or equity stake)
d) a private (" hard money") lender, usually also in second position, or possibly in third.
In Canada banks lend up to 80% LTV (loan-to-value) by law for an investment property. Thus to get less than 20% from your own jeans you need a partner b) to d).
The seller might be the cheapest source, at 0% to 5%, whereas c) and d) is usually more expensive.
Keep in mind that banks may not lend 80% if other parties are involved, or they ask for add'l personal guarantees / collateral from you or other sources, say your JV partner.
Fine tuning this approach take a while to learn and a few deals to master.