Employers in Canada must deduct CPP/QPP contributions from their employees’ pay. In addition, they must also provide a matching contribution and remit these amounts to the government. The contributions are based on the annual pensionable earnings that are set by the CRA each year. Once the employee is at age to retire or becomes disabled, these benefits are provided as income.

Canadian Pension Plan (CPP) – employees over 18 years of age and before 70 years of age must contribute. The employee can file a CPT30 form with the CRA at the age of 65 or over to have these contributions stop.

Quebec Pension Plan (QPP) – employees who are over 18 years of age must contribute. The only exception is if the employee has a special exemption granted by the Quebec Government or the employee becomes disabled.

Resources:
What CRA considers pensionable earnings are always up-to-date here

Special CPP considerations and rulings here

Canadian Pension Plan full details here

Details on the Quebec Pension Plan is here