For a two-year program, do we need to show the full two years' tuition fees before visa or only one year?

You only need to show proof of funds for the first year's tuition fees, plus living expenses and transportation costs, when applying for a Canadian study permit for a two-year program. You do not need to pay or show funds for the full two years' tuition upfront.

Some colleges may have different payment policies, so confirm with your chosen institution if needed.