During the Civil War, in 1863 AD, President Lincoln announced the end of slavery. When the North won the war, in 1865, Congress and the states voted to change the Constitution to make slavery illegal, so all the people who were slaves in the South became free.
Some people chose to leave the plantations, now that they were free. Some of them moved to the North to work on the railroads or as house-cleaners or nannies or cooks, or to start their own businesses. Some people went out West to be settlers or cowboys, but Western states made laws preventing African-Americans from moving there. A few people went back to Africa.
But just like when the Austrian and Russian rulers freed their people in the 1850s and 1860s, most people just stayed about where they were before. They still didn't own any land to farm, and if they tried to get land, white people attacked them. A lot of people kept on planting and picking cotton, but now they were sharecroppers instead of slaves. For a lot of people, it didn't make much difference, only there were not so many beatings and you didn't have your kids or your husband taken away from you anymore. But white people still terrified black people by killing them for nothing, or for almost nothing, and no white judge or jury in the south would send any white man to jail for killing a black man. Black people accused of crimes were often killed without a trial, by lynching.
Nannying ca. 1900
White workers' unions usually didn't let black people join, and white owners often used black workers as strike-breakers or paid them lower wages, black people started their own unions, or joined new unions like the STFU, the Southern Tenant Farmers Union, that had both white and black members. These helped black people to get better pay and better working arrangements.
About fifty years later, though, in 1910, the cotton was ruined by a kind of insect called a boll weevil. A lot of sharecroppers were starving from not having enough cotton to sell for food. Besides, it was getting cheaper to raise cotton using machines instead of people. So a lot more people decided to leave the South and go north to work. Because white people wouldn't hire them for any good jobs, they still worked mostly as servants - as nannies, or cooks, or taking care of sick people - or in hard, dirty jobs like cleaning streets or building railroads.