guys
i need to know how long does it take afetr sending I-846 and paied IV bill

Nobody will be able to tell you this as every case is unique. Next thing you will get is the DS-230 (see the guides for more information) and they will review your I-864 and decide if the financial funds provided by the sponsor(s) are sufficient. Once the intending immigrant has all the documents for the DS-230 and the form is filled out you have to send that in and then NVC will check the documents and information provided. It all depends on what they decide upon once they receive the information and documentation required. My guess is it could be anywhere between a few weeks and a couple months. But thats just my guess and it could be a lot quicker.

can i send I-864 by e-mail or i have to use mail only plz help me

mail only...