Unlike The Conjuring, Annabelle is "completely fictional." Ha ha. That creepy doll drove its own sub-plot in The Conjuring. Here, it's the star! The film takes place in the studio's version of the Marvel Cinematic Universe -- a horror universe based on the career of the regrettable Ed and Lorraine Warren, who were at least pretty good at selling themselves as ghost-busters. They're referenced in this movie but aren't part of the main plot, which is instead an origin story for that creepy doll.
Ah, that creepy doll. In 'reality,' the creepy doll was a large Raggedy Ann. Such a representation would aid with my suspension of disbelief, but the copyright holders of the Raggedy Ann and Andy dolls wouldn't allow the producers of The Conjuring or Annabelle to use their doll in the movies. So instead we get a doll which looks ridiculously malevolent even before it turns into a Hell-powered terror-machine. Anyone who wanted this doll would have to be insane. There is probably a better movie in that concept somewhere.
The plot revelations and narrative beats of Annabelle are familiar, though delivered with a certain level of competence. The lead actress (hilariously named Annabelle in real life) carries the weight of the often ridiculous narrative well; the other actors don't have a lot to do, though old pros Alfre Woodard and Tony Amendola do as much as they can with the material. I wish the creators of movies that use Roman Catholicism would at least take time to read Roman Catholicism for Dummies. I really do. Lightly recommended.