If the President vetoes the Bill, it is returned to the chamber of Congress where it originated, along with the President’s objections.
Congress then has a choice.
It can allow the veto to stand, in which case the Bill does not become law.
It can also can attempt to override the President’s veto.
Overriding a veto requires a much higher level of congressional support than passing most legislation in the first place.
Both chambers must approve the bill again by a two-thirds vote.
If two-thirds of the House and two-thirds of the Senate vote to override the veto, the Bill becomes law without the President’s signature.
If either chamber fails to reach the two-thirds threshold, the veto stands and the Bill does not become law.