An animated overlay requires what is known as an Alpha Channel in order to overlay in front of the main video. Unfortunately, Apple has not integrated Alpha Channel support for iOS apps, so there is not a way to import custom animated overlays into Switcher Studio.
However, Switcher Studio includes several built-in animated assets that are customizable. For example, on lower third assets, you can change the text size, alignment, font, style, and color, the background, the size and location.
For a full list of built-in asset types and links for more in-depth information on how to custom them, check out the article Asset Creation in Switcher Studio.