Submit your customs and immigration declaration online using Advance Declaration up to 72 hours before you arrive in Canada. Among those exempted from this new requirement are U.S. citizens and travellers with a valid visa.The eTA can be obtained online through a short application form on the Government of Canada's website and electronically linked to your passport number. Visa-exempt foreign nationals need an eTA to fly to or transit through a Canadian airport. To whom it may concern,. Passengers flying to Canada require an Electronic Travel Authorization (eTA). The application needs to be completed 72 hours prior to your departure date. You will require a visitor visa (also called a temporary resident visa) to attend the conference in Canada. Then you'll just complete the final steps onboard. Electronic System for Travel Authorization (ESTA).