Visitor or new immigrant plans are for sudden illness and accident. They are not meant for wellness doctor visits, but they are not only for emergency room visits either. If your visitor is sick and wants to visit a doctor or go to an Urgent Care Center, this sort of visit will also be covered.
Generally, at a hospital, they should be able to call and arrange payment with the insurance company. It may be at a doctor’s office, they will say “we don’t take this insurance” which means that they do not want to make the call for you.
In that case, you will have to pay up front and submit a claim for reimbursement. In most cases, you will have to submit a claim to explain what happened to the insurance company.