[ad_1]
@newbie63 WP-Optimize provides page caching meaning that when a user requests a page, the generated HTML response is cached. When another user requests the same page, the cached HTML response is served instead of newly generating an HTML response. You can go to Dashboard => WP-Optimize => Cache and turn on caching.
What site health checkup says is to use an object cache. In simple terms, Object cache caches the result of database queries. When the same query needs to be done again, it serves result from cache rather than fresh database query. This is something your hosting provider can provide. Based on the type of object cache (Redis, Memcached) they provide you need to use respective plugin