The Ewells are considered to be the disgrace of Maycomb for three generations. They are not known for having a strong work ethic or care about education. They don't want to improve their lives in any way and are content to continue to live in ignorance.
Throughout the novel, we come to know more and more about the Ewells. In the first couple of chapters, we are introduced to why they don't go to school. When Scout starts school for the first time, she has a hard time. School was not what she expected it to be. Miss. Caroline, her teacher, is new to town and doesn't know the townspeople. When something is said about the Ewells, Scout is more than happy to speak up and let her new teacher know the ways of this family.
"He's one of the Ewell's, ma'am' and I wondered if this explanation would be as unsuccessful as my attempt. But Miss. Caroline seemed willing to listen. Whole school's full of 'em. They come first day every year then leave. The truant lady gets 'em here 'cause she threatens 'em with the sheriff, but she's give up tryin' to hold 'em. She reckons she's carried out the law just gettin' their names on the roll and running 'em here the first day. You're supposed to mark 'em absent the rest of the year."
Scout goes on to tell the new teacher that the kids don't have a mother, and their father just doesn't care what they do. The whole town just turns a blind eye to them. The landowners look the other way when Mr. Ewell poaches on their land, because they feel sorry for his children. This first introduction of the Ewells, sets us up for the rest of the novel, and just how bad this family truly is.