If you have already NETFILED your income tax return, you will need to wait until you receive your Notice of Assessment before making an adjustment request.

https://turbotax.community.intuit.ca/replies/2647992

To indicate that you're eligible for the Disability Tax Credit in online editions of TurboTax:

1. Sign in to your TurboTax account and open your return.
2. In the upper-right corner of your screen, select Find.
3. In the Find window, type Disability and select Go.

https://turbotax.community.intuit.ca/replies/3484165