In Ontario, the traditional Amish largely opt out of social programs and public education that they're eligible for; they manage as they can within their communities privately, perhaps hiring outside services as necessary. Some make use of provincial health services; you can get the documentation and ID for that with some paperwork (which they probably have - income tax statements and birth certificates, etc.) in person at government offices. Otherwise the only mandatory interaction with the state is basically birth registrations and paying income taxes. Both of those can still be done with paper forms by mail or in-person, at least for now.