First, it is the team, not just the dog that is certified.
Getting my Self-Trained Service Dog legally certified as a service dog
If you live in British Columbia, Alberta or Nova Scotia, you need to contact the regulating bodies that will test you and your dog in person, make sure you are both ready to take the assessment test, fill out the forms, have the designated medical provider and veterinarian fill out the forms, and pay the fees. Be prepared to cover your own travel and accommodation costs unless you are on social assistance. Each province also requires an annual or biannual renewal.
If you live in any of the other provinces that do not offer this option, you have two options:
1). Contact each of the 3 provinces who certify owner-trainers and ask if they certify out-of-province teams. Find out if they will accept forms filled out by medical provider and veterinarian from another province. If so, then arrange for the test. Be prepared to cover your own travel and accommodation costs unless you are on social assistance. Each province also requires an annual or biannual renewal.
2). Contact organizations accredited by Assistance Dogs International and and find out if any of them will certify owner-trained teams. They may require you to train with them for a period of time so they are comfortable that your team will not be a liability issue for them. Make sure they have the same training philosophy as you do before committing to working with them. Ask what equipment and tools they use on their dogs and make sure you are comfortable with that as well. You will have to travel to them and likely provide your own testing, training, travel and accommodation costs etc.
All legally recognized tests are done in-person and issued either by an organization accredited by Assistance Dogs International (ADI) or a body appointed by the provincial government. None of them will issue a certificate without meeting you and your dog together in-person.