If you’re travelling to Vancouver from outside of Canada, you will probably need a VISA.
Please note that only U.S. and Canadian citizens can travel to Canada without any authorization. If you are not a Canadian or U.S. citizen, you will be required to obtain a visa or an Eletronic Travel Authorization (eTA) to enter Canada. Check this webpage to find out if you need an eTA or a visitor visa.
The eTA is a new entry requirement for visa-exempt foreign nationals travelling to Canada by air. It allows Canada to screen travellers before they arrive so you will need to apply before you book your flight to Canada.
The authorization is electronically linked to your passport and is valid for five years or until your passport expires, whichever comes first.
Apply for your eTA directly through the official webpage of the Canadian government. Most requests get approved within minutes. However, some applications can take several days to process so do apply as soon as you can.