221g blue form, no docs to submit

[Patilmumbai]

Hi,
Could any one suggest being in similar situation.
We visited mumbai consulate with family for h1b and h4 applications. interview went ok, but in the end the officer handed over 221 g blue form and asked us to drop passport after July. No additional ticks to submit any other document.

Docs to be dropped at Dropbox location.

What does this mean?

Regards