Some people say that when Charles Dickens wrote David Copperfield, he based the main character on his own life story. Same goes for Tennessee Williams' play, "A Streetcar Named Desire."
Loretta Lynn has some songs like this—fictionalized or semi-fictionalized accounts of things that are really personal to her. Most of her songs draw from some real part of her life experience.
Lynn said in an interview, "With every song I've ever written, there's a part of me in it. Of course, I'm not going to say what all they were 'cause it would be hard to even do that, but I know there’s a part of me in every song I've wrote, if it's just half a line." (Source)
Another time she said, "I write about life. And, boy, I got in all kinds of trouble. But that's what people are interested in. They're not interested in fantasy stuff." (Source) The trouble she's talking about is with her song, "The Pill," a tune about female birth control that got her banned from many a radio station.
But "Coal Miner's Daughter" isn't just a song based on or inspired by Lynn's personal experience. Instead, the song is directly about her personal experience: it tells the real story of Lynn's life growing up. It's true autobiography, closer to The Autobiography of Benjamin Franklin or even The Diary of Anne Frank than David Copperfield.
As one of the best-known female country singers ever, Lynn paved the way for other women to sing songs about their own personal stories. When you hear Taylor Swift singing about being "a careless man's careful daughter," or Dolly Parton riffing on hard work or heartbreak, the inspiration and influence of "Coal Miner's Daughter" is probably there.