Question

What must be true of a bill which has become law at a federal level?

Answer 1

One thing that is true of a bill which has become law at a federal level is that "It must have passed both the House and the Senate," since sometimes bills can become law without the President's signature, if there are enough votes to override a veto. 

Answer 2

It is true that at a federal level, a law must have passed both the House and the Senate. Only after the aprooval of both chambers of the Congress a bill can become a law.

The other statements are wrong:

-When a bill voted by Congress reaches the President, it can approve or veto it, which are the typical actions. But there are ways in which the bill can be approved without the signature of the President: if the President does not sign, after 10 days the bill is approved automatically if the Congress is in session (if it is not in session, the project is rejected); Also, even if the President vetoes the law, Congress can override that veto with the support of 2/3 of the congressmen present in the two chambers, in this way the bill becomes a law.

-It is not necessary to the federal law to be in favor of the interests of all Americans.

-The bills can enter by either of the two chambers with no difference.