I deleted the Antenna Tv app and now I need it. I cant find it in any category or search. How can I get it back?
Are you sure there was an app? I don't see one either. It's likely there was one, but they (the developers, not Roku) dropped support and it was removed from the store. As long as you didn't delete it, it apparently was allowed to continue access.
If you mean you removed the Antenna/OTA input tile from a RokuTV, you can re-enable access by navigating to Settings/TV Inputs/ [Live TV].