What do i need to bring with me to canada?

I'm going to Niagara Falls this summer from the U.S to Canada and i will be crossing borders. I kept on getting different answers on what i need to take with me? I'll be taking my 2 daughters with me, and myself. We're going to drive there too, from Pennsylvania to the Canadian side of Niagara falls. What will i need? Like passports, birth certificates, etc. Will i need papers to prove the children are mine too?