It is considered a side-story that is canon to the world but does not heavily impact the main television plot.
While this prologue focuses on Éclair's difficult morning and her journey toward the town where she eventually collapses, it sets the stage for her fateful encounter with Lucy Heartfilia , which kicks off the main plot of the movie. Where It Fits in the Timeline Fairy Tail: Houou no Miko Episode 1
This special is based on a one-shot manga by series creator Hiro Mashima and focuses on the character before she meets the Fairy Tail guild. It is considered a side-story that is canon