What docs I have to file for my girlfriend
She is in Canada, and I live in US. Some friends told me that if I marry her outside of US, like in Canada, she can get green card faster.
We are 2 years together and I often go to Canada to see her. She is not Canadian citizen and she is illegally there.
Do you know what forms I should file, and should I marry her in Canada or in the US?
What is your status in the U.S.? That will determine the possibilities.
Assuming that you are a US citizen and can sponsor her for a GC or K-1, she will have issues with the US consulate in Montreal. Since she has no legal status in Canada, they will not entertain her immigrant or K-1 visa request.
She is not Canadian citizen and she is illegally there.
It doesnt really matter where you marry her. What matters is where she will go to interview for the green card. It cant be in Canada, because is there illegally, and it cant be inside the US because she (presumably) doesnt have a visa or other permission to enter the US legally. She will have to pursue the immigrant visa or K-1 visa at a US consulate in the country of her citizenship (or another country in which she has legal residence). So you could marry her in Canada, and then some months later she would travel back to her home country to interview at the consulate.