next.js/examples/api-routes-apollo-server-and-client-auth/pages/_app.tsx

import { ApolloProvider } from "@apollo/client";
import { useApollo } from "../apollo/client";

export default function App({ Component, pageProps }) {
  const apolloClient = useApollo(pageProps.initialApolloState);

  return (
    <ApolloProvider client={apolloClient}>
      <Component {...pageProps} />
    </ApolloProvider>
  );
}