From the Executive Summary: "Under the Biden-Harris Administration, the Department of Homeland Security (DHS) has been executing a comprehensive and deliberate strategy to secure our borders and build a safe, orderly, and humane immigration system. After inheriting a broken and dismantled immigration system, since January 2021 DHS has effectively managed an unprecedented number of noncitizens seeking to enter the United States and interdicted more drugs and disrupted more smuggling operations than ever before. The legal authority for enforcing our border security and immigration laws comes from Title 8 of the U.S Code. Among other things, Title 8 provides that individuals who cross the border without legal authorization are processed for removal and, ifunable to establish a legal basis to remain in the United States, promptly removed from the country."
U.S. Department of Homeland Security: http://www.dhs.gov/