What exactly is disability tax credit?

The disability tax credit (DTC) is a non-refundable tax credit that helps people with disabilities, or their supporting family member, reduce the amount of income tax they may have to pay. You can read more about it, and apply, at: https://www.canada.ca/en/revenue-agency/services/tax/individuals/segments/tax-credits-deductions-persons-disabilities/disability-tax-credit.html.