After debate in either house of Congress the bill is sent to the appropriate committee for review and revisions. Sometimes hearings are held to gather expert testimony, and the committee issues a report with its recommendations. There may also be committee prints--documents for the use of a committee in their work, but not the formal report of the committee. These prints may contain committee rules, revised versions of bills or preliminary reports.
If a committee does not act on a bill it is said to "die" and will not progress further. If approved, the bill will return to the House or Senate for approval.