Prospective undergraduates interested in studying Mechanical Engineering at Stanford apply to the university through the Undergraduate Admissions Office not directly to the Mechanical Engineering Department. This allows Stanford students to explore a wide range of possible major fields before committing to a specific one. Once convinced that Mechanical Engineering is the appropriate field, students may "declare" the major during the sophomore or junior year. The major is open to all Stanford undergraduate students in good academic standing. Information for new admission, requesting an application, transferring to Stanford and other matters is available from Stanford Undergraduate Admissions.
Information for new admission, requesting an application, transferring to Stanford and other matters related to Stanford admissions can be found at the ungraduate admissions website.