If USCIS determines that there are more immigrant visas available for a fiscal year than there are known applicants for such visas, USCIS will state on this page that you may use the Dates for Filing Visa Applications chart. Otherwise, USCIS will indicate on this page that you must use the Application Final Action Dates chart to determine when you may file your adjustment of status application.
FAQs: H-1B visa transfer before arrival into the USA|| Employee paying for green card and H-1B premium costs || Using an old H-1B visa stamp of a different employer
FAQ: Converting from B visa to any other status such as H-1B, etc.