In the United States Congress, a joint resolution is a legislative measure that requires passage by the Senate and the House of Representatives and is presented to the president for their approval or disapproval.
Both must be passed, in exactly the same form, by both chambers of Congress, and signed by the President (or, re-passed in override of a presidential veto; or, remain unsigned for ten days while Congress is in session) to become a law.
Only joint resolutions may be used to propose amendments to the United States Constitution, and these do not require the approval of the President.
While either a bill or joint resolution can be used to create a law, the two generally have different purposes.
Bills are generally used to add, repeal, or amend laws codified in the United States Code or Statutes at Large, and provide policy and program authorizations.