To apply for a mortgage in Canada, start by checking your credit score, reducing debt, and saving for a down payment. Obtain a mortgage pre-qualification or pre-approval to understand your borrowing capacity. Choose a mortgage type, compare rates, and consider using a mortgage broker for assistance. Save at least 20% for a down payment, and budget for closing costs. Assess your mortgage affordability using calculators and understand the application process, which includes submitting financial documents and possibly negotiating terms if not approved.