Optum offer letter

Hi folks,

I’ve been recently interviewed at Optum Hyderabad for senior DevOps Engineer. They have verbally revealed the offer.

HR sent an Email to share few documents ( payslips, pan and aadhar card )

1. when can i expect offer letter
2. Are they going to do the BGV first and then release the offer letter?
3. will I receive separate Email for BGV?

Thanks in advance.