They were not allowed to vote. They were not allowed to drink from the same fountains as whites, were not allowed to be served in restaurants and motels, and more that I can't think of at this minute. Jim Crowe laws were meant to keep blacks as second class citizens after slavery, so they still weren't really free. Only after the Civil Rights Movement were blacks permitted to do the things I listed above, after the abolishment of Jim Crowe laws. Blacks had a long fight to become equal in the south and there are still areas that are totally white and racist.
It made life a lot harder than it was originally. With these laws it made life worse for them. They were treated like dirt.