If she wants to enter US, yes ; she should have a visa if not from a visa exempt country.
But in general, one should just go there to the US border, and ask for a form to be stamped as rejected; which will indicate you have exited Canadian border.
but this is not a visa. It is sort of rejection from US. she should inform them that she is going to land in Canada, and they should take care of the issue.
She can drive to the border, and do all stuff. if everything goes fine, should not take more than an 1 hour.
But in general, one should just go there to the US border, and ask for a form to be stamped as rejected; which will indicate you have exited Canadian border.
but this is not a visa. It is sort of rejection from US. she should inform them that she is going to land in Canada, and they should take care of the issue.
She can drive to the border, and do all stuff. if everything goes fine, should not take more than an 1 hour.