Did you already claim the contribution on your 2021 tax return? 

No I did not. That's why can I still claim it this year or the next. If yes, how do I add it in the first place in CRA records so that it shows up next year

If you didn't claim it for the tax year 2021, you should do an adjustment. 

If you have used TurboTax Online, you can use the ReFILE option by sign in to your account and, on the side of the NETFILE return, you will have a ReFILE button. In TurboTax Online, ReFile is not available for Quebec residents.

If you're using TurboTax Desktop, when you open your 2024 software, you click on “Change a filed return”, choose the return you want to modify, click on modify return (in the NETFILE section) and follow the steps to apply the changes and ReFILE. If the steps are done in this order, the ReFILE button will be there.

In all cases, regardless of the software version used, you can do so directly in your My Account CRA and Revenu Québec, or by mail, by completing the following forms:

CRA: T1-ADJ T1 Adjustment Request

Revenu Québec: Request for an Adjustment to an Income Tax Return
 

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