Unless included in your business income, Trustee, Executor, or Liquidator fees paid to you for acting as an executor is considered income from an office or employment. Executor fees are to be reported on a T4 slip. The trust that was responsible for the Trust was required to complete a T4 for you as executor.

To quote their page: "Unless included in your business income, trustee, executor, or liquidator fees paid to you for acting as an executor is income from an office or employment. As the executor, you must report these fees on a T4 slip. For more information see "Employment by a Trustee" in Chapter 1 of the T4001, Employers' Guide - Payroll Deductions and Remittances."

https://www.canada.ca/en/revenue-agency/services/tax/individuals/life-events/what-when-someone-died/...