The Annabelle doll was created as part of the 'Conjuring' universe. It was based on a supposedly haunted Raggedy Ann doll. In real life, there were claims of strange happenings associated with the doll. It was said to move on its own, and there were various spooky incidents reported by those who encountered it. Ed and Lorraine Warren, paranormal investigators, got involved with the case and later it became the inspiration for the Annabelle character in horror movies.
Well, it is. The story behind the Annabelle doll in real life had some spooky incidents reported. The makers of 'Annabelle Creation' used those real - life accounts as inspiration. For example, the doll was said to move on its own and strange things happened around it. So, they built a horror movie plot around these basic ideas from the true story.
Annabelle Creation is purely fictional. The story and characters are made up by the filmmakers to scare and thrill the audience. There's no real-life basis for it.