What did the emancipaton declaration do?

The "Emancipation Proclamation" formally emancipated all slaves in any state of the Confederate States of America that did not return to Union control by January 1, 1863. Specifically:

... all persons held as slaves within any State or designated part of a State, the people whereof shall then be in rebellion against the United States, shall be then, thenceforward, and forever free; and the Executive Government of the United States, including the military and naval authority thereof, will recognize and maintain the freedom of such persons, and will do no act or acts to repress such persons, or any of them, in any efforts they may make for their actual freedom.

None did return and the actual order, signed and issued January 1, 1863, took effect except in locations where the Union had already mostly regained control.

The Proclamation had at least 3 effects:

It made abolition of slavery a goal of the Civil War (in addition to reunification) - which helped win more support for the war among the war-weary citizens of the North and undermine the anti-war efforts of the Northern "Copperhead Democrats"

It undermined support by Britain and France for the South - since those nations had abolished slavery

It helped disrupt agriculture and industry in the South by encouraging Southern slaves to flee the plantations, farms, etc.

It also granted immediate freedom to slaves living in Confederate areas now under the control of Union forces including parts of eastern North Carolina, the Mississippi Valley, northern Alabama, the Shenandoah Valley of Virginia, a large part of Arkansas, and the Sea Islands of Georgia and South Carolina. Many of those former Southern slaves had been declared "contraband of war" - in other Words, "captured goods" so they were still considered property, but now they belonged to the Union forces and were often put to work laboring for the Union forces - digging trenches, cooking, etc. A few Union commanders declared any slaves who escaped to the areas under their control were now free - but those commanders were usually soon replaced since they really didn't have legal authority to free the slaves. Northern states such as Missouri, Kentucky, Tennessee, Maryland, Delaware, and the newly created West Virginia that still permitted slavery were exempt from the Proclamation and slavery remained legal there until either the state abolished slavery within its boundaries or until the 13th Amendment was passes.