How can a bill can become a law without the presidents signature

If he specifically rejects the bill, called a veto, the bill returns to Congress. There it is voted on again, and if both houses of Congress pass the bill again, but this time by a two-thirds majority, then the bill becomes law without the President's signature.

“a committee reviews the bill and marks it up to make it more viable and to reflect interests 

yes he can but hardly

explanation: