meeting with prisoners El Reno Federal Correctional Institution in 2015
Federal pardon in the United States is the action of the of the President that United States or completely sets aside the punishment for a commutes (lessens) . The authority to take such action is granted to the president by federal crime of the Article II, Section 2, Clause 1 , which states, "The president shall ... have power to grant reprieves and pardons for offenses against the United States, except in cases of U.S. Constitution ." The impeachment has interpreted this language to include the power to grant pardons, conditional pardons, commutations of sentence, conditional commutations of sentence, remissions of fines and forfeitures, U.S. Supreme Court , and respites . amnesties The pardon can also be used for a presumptive case, such as when President Gerald Ford pardoned Nixon over any possible crimes regarding the  Watergate scandal. 
A president cannot pardon someone for state or local crimes.
Experts disagree as to whether a president can pardon himself.