According to article 1 section 8 states that “The Congress shall have power to lay and collect taxes, duties, imposts and excises, to pay the debts and provide for the common defense and general welfare of the United States; but all duties, imposts and excises shall be uniform throughout the United States”. Every tax bill passed must be approved by the US congress and also sent to the president of the United States and become a law. They have the power to create tax laws.

http://www.law.cornell.edu/constitution/articlei

According to ushistory.org, “Before a bill becomes a law it must pass both houses of Congress and signed into law by the President. It may begin its journey at any time, but it must be passed during the same congressional session of its proposal, a period of one year. If it does not complete the process, it is dropped, and can only be revived through reintroduction and going through the whole process again”. Before the bills become law, they go through a committee consideration and floor debate. In most cases both stages are important in successfully becoming a bill. http://www.ushistory.org/gov/6e.asp The Common body tax laws are made up of the internal Revenue Code, Treasury Regulations, Court Cases, and the IRS. It is governed by regulations created by the IRS. According to the lawdictionary.org, “it is the legal framework that denotes the taxing authority and regulations of a given country's tax laws. The term is most often used to describe the framework that governs the American tax code. Since there are several key agencies that have the authority to levy taxes, penalties, fees and other duties on American citizens, the Common Body of Tax Law is quite complex”.
Law Dictionary: http://thelawdictionary.org/article/what-comprises-the-common-body-of-tax-law/#ixzz2rYTKJN4W
According to the IRS.gov, “The mission of the Internal Revenue