The problem you’re encountering has to do with TypeScript, the programming language you’re using, not being able to find “type declarations” for the ga-gtag module. Type declarations help TypeScript understand the types of variables, parameters and returns used in a library, thus making your code safer and easier to manage. If a library doesn’t come with its own type declarations, and they’re not available through DefinitelyTyped (a large repository of community-contributed TypeScript definitions), you can create a basic one yourself. In your case, TypeScript is saying it can’t find the types for ga-gtag likely because the library either doesn’t include them or they are not available through DefinitelyTyped.