From the summary of Congress’s Authority to Influence and Control Executive Branch Agencies (R45442, Dec. 19, 2018):
The Constitution neither establishes administrative agencies nor explicitly prescribes the manner by which they may be created. Even so, the Supreme Court has generally recognized that Congress has broad constitutional authority to establish and shape the federal bureaucracy. Congress may use its Article I lawmaking powers to create federal agencies and individual offices within those agencies, design agencies’ basic structures and operations, and prescribe, subject to certain constitutional limitations, how those holding agency offices are appointed and removed. Congress also may enumerate the powers, duties, and functions to be exercised by agencies, as well as directly counteract, through later legislation, certain agency actions implementing delegated authority.