The Government of Canada’s official website to apply for an eTA. It only costs $7 CAD. Most eTA applications are approved within minutes of applying.
New entry requirement now in effect: visa-exempt foreign nationals who fly to or transit through Canada need an Electronic Travel Authorization (eTA). Exceptions include U.S. citizens and travellers with a valid Canadian visa. Canadian citizens, including dual citizens, and Canadian permanent residents cannot apply for an eTA.
Entry requirements for other methods of travel (land, sea) have not changed.