Need guidance for H1B process in contract position

(On behalf of a friend) I have been offered a contractual position at Gilead sciences in Seattle for a period of 9 months expiring in August 15 2021. I was working with a staffing company for this role. I am currently on F1 visa and require an employer to file for my H1B in 2021. I have a couple of questions for someone who has been in the same situation as I, where the contract position is expiring (August 2021) before the H1B kicks in (October 2021) 1. So the contract period ends on Aug 15, 2021. If my H-1B gets approved next year and I want to move from one employer to another (aka the staffing company who files my H-1B to Gilead), when can I do that? 2. Also are staffing companies who send me to client sites allowed to file H-1B? Highly appreciate of anyone can respond to these questions of mine. Thank you!! 🙂🙂 #gilead #gileadsciences #h1b #h1btransfer #contractor #staffing360solutions