The Manitoba Renters Tax Credit is only for 2022 and later years. Before that there was a renter component to the education property tax credit. Either way, they are both in the Provincial section of TurboTax.

To add these credits to your previous year's returns, you would have to adjust them using either ReFIle or another method as per the CRA. 

This TurboTax Canada FAQ tells you how to use ReFile: https://turbotax.community.intuit.ca/turbotax-support/en-ca/help-article/accounting-bookkeeping/file... ReFile is not avaialble for TurboTax Online 2021 or earlier, or TurboTax Desktop 2019 or earlier.

This Canada Revenue Agency (CRA) web page lists other ways to can adjust your return: https://www.canada.ca/en/revenue-agency/services/tax/individuals/topics/about-your-tax-return/change...