Thank you. Are there requirements on 1) how many years said contractor had to work in such system abroad prior to being eligible to apply for H1B, 2) What are G

Thank you. Are there requirements on 1) how many years said contractor had to work in such system abroad prior to being eligible to apply for H1B, 2) What are Government requirements to proof a bona-fide partnership with this contractor? Will invoices from Europe suffice?