How to authorize a tax representative — and autofill 9966 with my-id.ca
Appoint or cancel an Ontario tax representative without retyping both parties' details
Taxpayers appointing or cancelling a Ministry of Finance representative repeat legal names, addresses, account identifiers, and representative contact details on every authorization package. This guide is an example of storing them once in my-id.ca.
Official form and source
Start from the official source and always use the current version — form numbers and links can change:
- Service page: Corporations tax forms and publications — ontario.ca
- Form (Central Forms Repository): Authorizing or Cancelling a Representative — 9966
What this form is about
Form 9966 is Authorizing or Cancelling a Representative for Ontario Ministry of Finance tax programs — confirm which authorization form your account requires on ontario.ca.
Before you start: what to gather
- Taxpayer legal name and mailing address.
- Business number or Ontario tax account identifiers if applicable.
- Representative name, firm, address, and contact details.
- Authorization or cancellation date and scope — confirm on ontario.ca.
Confirm the current process on ontario.ca.
How my-id.ca makes it faster
- Save it once. Store your taxpayer and representative name and address details in your my-id.ca profile.
- Keep documents ready. Upload supporting documents to my-id.ca Files so you are not searching at form time.
- Autofill the form. Use the my-id.ca Chrome extension on a web form, or fill a PDF from your saved profile inside my-id.ca.
- Review and submit yourself through the official channel.
Why do it in my-id.ca
Related Ontario forms repeat the same personal details. Captured once in my-id.ca — stored in Canada, with AI on its own servers — every form starts mostly complete.
Frequently asked questions
- When should I use form 9966 instead of 013-0009?
- Ontario publishes more than one representative authorization form — confirm the current version for your tax program on ontario.ca.
- How does my-id.ca help?
- It autofills taxpayer and representative name and address fields.
- Does my-id.ca authorize representation?
- No — you sign and file; my-id.ca only autofills repeating identity fields.
Fill it once. Reuse it everywhere.
Save your information in my-id.ca once, then autofill this form and the next one — web forms with the Chrome extension, PDFs right in the app. Your data is stored in Canada and AI runs on my-id.ca's own servers, never sent to third-party AI providers.