Hi @WendyMcAlpine
If you forgot to claim an expense on a previous tax return, you can file an adjustment request with the CRA for the relevant tax year. You can do this by logging into your CRA My Account or by filling out Form T1-ADJ and mailing it to the CRA. You will need to provide details of the missed expense, including the amount and supporting documentation. It's important to note that there are limits on how far back you can adjust your tax return, which is typically within 10 years of the filing deadline or date of assessment.