I've heard that the Old Age Security pension is not taxable. The pension is taxable. However, the Guaranteed Income Supplement and spouse allowances are not taxable. All types of taxable income, except the Old Age Security Pension, are taken into account when calculating your net income. You should apply four months before the date on which you wish to begin receiving your pension or, at the very latest, at least one month before.
Some conditions apply.
If both spouses have not contributed to the Plan, than one of the spouses must be at least 60 years of age. The new income amounts entered under the name of each spouse will give entitlement to a retirement pension and may give entitlement to a disability pension or survivors' benefits. You should apply without delay. If you have completely stopped working, your pension will be paid to you retroactively. Some conditions apply.