I-94 card

Hello; I am in US as a volunteer, planning to stay for a year.
After I entered U.S., the employer asked me to send them a copy of I-94 card, which tells me when I suppose to go back to Canada (I think Canadians can stay in U.S. up to 6 months). And, I never received it. When I told them about it, they said then, I can stay for a year without going back to Canada.
Is that true? where should I ask for the accurate information?
Thank you

That's not true. Canadians generally don't get an I-94 when they enter as a visitor in the standard B category (which is specifically stated at the top of the I-94 card).

USCIS work on the basis that Canadians can only stay in the US for six months in a calendar year. It's a bit more complicated as there are exceptions in various situations, but generally speaking, it's six months maximum.

do you have some sort of visa that allows you to volunteer in the US? Did you tell the POE that you were coming here to volunteer?

No, I didn't need any visa to enter US, and I told POE that I'm coming to volunteer. I did not have any problem entering US. I mean, they just asked me why I'm coming. So, I still have to go back to Canada before 6 months, right?
Thanks for the quick responses guys!

Yes.

lucky you. Recently more and more people are being denied entry to the US if they say they are there to volunteer, and some have even been barred from re-entry, just because of cranky POE officers!

Technically I think you're supposed to get some sort of visa, only no one really knows which one. Not even border guards.