Hi. How long it takes to transfer H1b to immigration visa sponsored by US citizen spouse. Secondly, are the immigration documents filed at the time of marriage, and does the marriage needs to be registered at civil court. The couple is in USA.

There is no "transfer." the process is called adjustment of status. Generally 90 days to get an EAD and AP. Total 4-8 months for the 245 interview.

USCIS filing can be done any time after the marriage. Does not need to be a civil ceremony.

I trust this is responsive to your inquiry.