Thank you for your question!
As per CRA:
If you were not a resident of Quebec on December 31, 2020, and you contributed more to the Canada Pension Plan (CPP) than you had to (see line 30800), claim the difference on this line. The CRA will refund the excess contributions to you or use them to reduce your balance owing.
If you were a resident of Quebec on December 31, 2020, this line does not apply to you. Claim the excess amount on your provincial income tax return for Quebec.
To calculate your overpayment, see Have you contributed too much?
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