This TurboTax FAQ tells you how do to enter RRSP contributions in TurboTax Online:
https://turbotax.community.intuit.ca/turbotax-support/en-ca/help-article/retirement-benefits/enter-r...
This FAQ has more information on changing your return using ReFile: https://turbotax.community.intuit.ca/community/tax-return-amendment/help/i-have-filed-my-tax-return-...
