can company give letter of consent

Dear,

i have a pvt ltd co. with a registered address X, and i and my friend is a director in it..
now i want to start my proprietorship business at same address. there is not going to be any consideration paid...

on gst registration page can i choose the option "consent" or "shared"???

and can co. give a normal consent on its letter head whereby i can oprate my proprietorship business...???

what other docs required along with consent letter??