While this could be talking about Wanda’s own brand of witchcraft, similar to Doctor Strange, it’s more than likely talking about her ability to change reality on a whim. Wanda exhibited this ability most famously in the comic book story “House of M,” in which Wanda recreates the world to be ruled by mutants instead of humans, while also granting everyone’s deepest desires.
In the newest issue of TV Guide Magazine, Elizabeth Olsen talks about the magic show they put on for West View and reveals that the show will explore more of Wanda’s abilities only seen in the comics. Olsen explains that “She’s a magician’s assistant, helping [Vision] but doing all the tricks for him and not letting the audience know” and that “It’s a very funny, gaggy” kind of moment.
Olsen goes on to explain that audiences will finally see abilities from Wanda previously only seen in the comics, hinting that these abilities have to do with how and why Wanda and Vision “progress to a different decade for a reason.” However, Olsen doesn’t specify what specific powers these will be.
It’s possible that during this magic show, while using her powers, Wanda might alter reality in a minor way, such as changing the shape of furniture, adding color to the world, or erasing an audience member from existence. As for why Olsen says this new ability is important in the context of the magic show, it could be related to Wanda’s line to Vision about how “something strange happened” before, during, or after the magic show.