Hi there!
The Veto process for a bill is when a the congress want's to make a law, and the president does not want/have to sign. This could be because the president may not agree with the Congress. However, the Congress can override the veto, if more than 2/3 of the house is voted for it to become a law. Then, and then only, can it become a law, without the president's signature.
I know this answer is late! But i hope it helps!
~Alexa
