Under the Immigration and Nationality Act (INA), any individual who arrives at a port of entry in the United States and who is inadmissible under either 8 U.S.C. § 1182(a)(6)(C) (misrepresentations and false claims to U.S. citizenship) or § 1182(a)(7) (lack of valid entry documents), is subject to expedited removal. See 8 U.S.C. § 1225(b)(1)(A)(i).
Additionally, the Secretary of DHS has the authority to apply expedited removal to any individual apprehended at a place other than a port of entry, who is inadmissible under either of those grounds, has not been admitted or paroled, and cannot show that he or she has been continuously present in the United States for two or more years. See 8 U.S.C. §§ 1225(b)(1)(A)(i), (iii).
A detailed 12-page Expedited Removal Guidance dated 02-17-2017 from National Immigration Project, ACLU, and American Immigration Council can be seen here. EXPEDITED REMOVAL: WHAT HAS CHANGED SINCE EXECUTIVE ORDER NO. 13767, BORDER SECURITY AND IMMIGRATION ENFORCEMENT IMPROVEMENTS (ISSUED ON JANUARY 25, 2017).