Brie Larson famously shot her scenes for Avengers: Endgame prior to production on Captain Marvel, which means that her costume was far from done.
"Her suit, every time you see it in the movie, when she's in her full costume, is digital. Again, the designs for those suits were not ready in time for us to photograph Brie," said Visual Effects Producer Jen Underdahl. "When you saw her at the beginning, as she's rescuing Tony Stark, when you see her come back, when she's talking to Nat in the Avengers compound, with Rocket and Nebula, and then in the final battle when she comes back and kind of saves the day, that's all the digital suit.