It would start with the law: for example, U.S. Code § 1324

(A)Any person who—
(i)knowing that a person is an alien, brings to or attempts to bring to the United States in any manner whatsoever such person at a place other than a designated port of entry or place other than as designated by the Commissioner, regardless of whether such alien has received prior official authorization to come to, enter, or reside in the United States and regardless of any future official action which may be taken with respect to such alien;
(ii)knowing or in reckless disregard of the fact that an alien has come to, entered, or remains in the United States in violation of law, transports, or moves or attempts to transport or move such alien within the United States by means of transportation or otherwise, in furtherance of such violation of law;
(iii)knowing or in reckless disregard of the fact that an alien has come to, entered, or remains in the United States in violation of law, conceals, harbors, or shields from detection, or attempts to conceal, harbor, or shield from detection, such alien in any place, including any building or any means of transportation;
(iv)encourages or induces an alien to come to, enter, or reside in the United States, knowing or in reckless disregard of the fact that such coming to, entry, or residence is or will be in violation of law; or
(v)
(I)engages in any conspiracy to commit any of the preceding acts, or
(II)aids or abets the commission of any of the preceding acts,
shall be punished as provided in subparagraph (B)

If you want to know about the punishments, read the rest here:
https://www.law.cornell.edu/uscode/text/8/1324