This is the ability to perform a task without making unnecessary errors. For some people, getting the details right is not a big priority. Other people are prepared to make enormous efforts to achieve perfection.
Accuracy is particularly important if your work is seen by the public and also if other people make decisions based on what you do.
For many people, accuracy is something that comes with practice. If this is something that you really find difficult, try slowing down and double checking your work before you move on.