My Petition was approved and now i have to collect the documents and to fill in the Application For Immigrant Visa and Alien Registration Forms DS-230 Part I and Part II. next step is to send all the documents to the national visa center and to wait for the interview. i was told that this process (until the date of interview) will take 3 months or a bit more. Can i come and visit USA while these 3 months of waiting? Is it legal that my father who lives in Chicago and is a citizen of USA would send me an Invitation. I want to go to the Usa for a month in summer, but we don't know what to do.