With all of the offers I've gotten, they offered me a visit in the email. For several of them, there was a strict limit on how much they'd be willing to pay for. I am a domestic applicant however, so that may a difference. Now that I think about it, I'm not sure all of them said they'd pay for the visit. Several of the offers to visit were just "our Open House is ___." If I were you, I'd ask them. As noojens said, I'm sure they'll LET you visit, but I doubt they'll cover the whole bill.