While there is not a separate app for Covidence right now, there is a mobile-optimised version of title and abstract screening! This can be accessed by navigating to Covidence from any mobile browser.
Screening on mobile has a few slight differences from desktop screening:
An option to undo your last vote is available from the expanded menu, accessible by clicking the three dots at the right. Also in this menu you can skip an abstract and it will be presented to you later.
Keyword highlights are available by selecting "Hide highlights" or "Show highlights" under the gear icon at the top right.
Finally, there is no "maybe" option when screening on a mobile device.