H1B when to file for extension?

[sentviaemail]

hi there,
I am on H1B status in USA and my visa expires in september 2007. so I would like to know that for premium process of extension , before how many days i have to submite my application for extension? and what documents do i need to attach with that application?
thanking you ,
bye

[answeredviaemail]

You can apply for extension 4 to 6 weeks before expiration.

Details at https://www.immihelp.com/usa-h1-visa/

Immihelp Support
No legal advice. Use at your own risk.