when do I have to submit I-864 after the fee is paid?

[rimmyj]

So I received my NVC Welcome Letter (PAOSF) about 10 days ago, and I filled out the DS261 and also paid the affidavit of support fee.
Question: which one should be my next step? submit the I-864 right away, or wait for the IV bill then submit the I-864 along with other documents needed?

[Jot18]

If you got the cover letter you can file I-864. But I recommend that wait for other documents and send in one packet. By sending early it won't process your application faster.