How is the President involved in the process of bills becoming laws?

Legislation is Introduced - Any member can introduce a piece of legislation. then it goes to the house then it goes to the senate if it is approved by the house then finally the president if all approve. he can veto it but if he does the senate and house can over power him and pass it anyways

he can also pass executive orders which doesn't require the sentat or house

The president has the power to veto the bill therefore it will not become a law or sign it and then it becomes a law