Yes, her name is already on the ballots, like RFK Jr is still on the ballots in many states, but the hope is her supporters will listen to her endorsement. Just because a person’s name is on the ballot doesn’t force people to vote for that person. Some people have voted already, some will continue to vote for her out of protest, some will continue to vote for her because they didn’t hear she dropped out or didn’t care. But the hope is enough people will hear that she dropped out and endorsed Harris that their votes will come through for Harris.
That’s a really hard guarantee to live up to. It almost sounds like an ominous threat.