Lincoln's Emancipation Proclamation occurred after the Battle of Gettysburg in 1863 and almost in the middle of the Civil War. Lincoln only declared the slaves of the Confederate occupied territories/States to be free. It may be considered similar to an executive order, but it had questionable legal and lasting effect.
The 13th Amendment abolished slavery permanently throughout the U.S.A. in December 1865 (after the end of the war) by legislative amendment of the Constitution. It was ratified by the States in haphazard fashion.