To receive a retirement pension, you must have contributed sufficiently to the Québec Pension Plan. You can start receiving a retirement pension as early as age 60, but the amount will be lower than if you wait until you reach the normal retirement age of 65.
Disability benefits: If you stop working before age 65 because of your health, your disability benefits will automatically be replaced by a retirement pension at age 65.
Surviving spouse’s pension: If you are receiving a retirement pension under the Québec Pension Plan and your spouse dies, the two pensions will be combined.

Further details

You can apply for your retirement pension one to three months before the date on which you would like to receive your first payment.

CompuPension is an online tool that can help you determine the best time to retire. Visit https://www.rrq.gouv.qc.ca/en/services/services_en_ligne/planification/Pages/simulation.aspx.