An amendment to the U.S. Constitution is required to change the presidential age requirement as stipulated in Article II, Section 1, Clause 5. This process entails a two-thirds vote in Congress or a constitutional convention, and subsequent ratification by three-fourths of the states.
To change the requirement that a candidate must be at least 35 years old to run for President, an amendment to the U.S. Constitution would be necessary.
The Constitution clearly states in Article II, Section 1, Clause 5 that no person except a natural born citizen, or a citizen at the time of the adoption of the Constitution, shall be eligible to the office of President unless they are at least 35 years old and have been a resident within the United States for at least 14 years.
Changing this requirement cannot be done by a mere law, a single president, or a constitutional convention alone—it would require a formal amendment process.
This involves either a two-thirds majority in both the House of Representatives and the Senate or a constitutional convention called for by two-thirds of the state legislatures, followed by ratification by three-fourths of the states.