What did the Emancipation Proclamation do?

What does this answer mean?

The Emancipation Proclamation freed the slaves in the Confederacy. USCIS accepts four versions: freed the slaves, freed slaves in the Confederacy, freed slaves in the Confederate states, or freed slaves in most Southern states.

President Abraham Lincoln issued the Proclamation on January 1, 1863, during the Civil War. It declared that all people held as slaves in the states and areas in rebellion against the United States were free from then on.

The details explain why USCIS accepts the narrower answers. The Proclamation applied only to the Confederate states and areas in rebellion. It didn't free people enslaved in the border states that stayed loyal to the Union, and freedom in practice depended on Union victories. It also announced that Black men would be accepted into the Union Army and Navy, and by the end of the war almost 200,000 Black soldiers and sailors had served.

Slavery ended everywhere in the country with the 13th Amendment, ratified in December 1865.

At the interview, say "freed the slaves."