find() does not only take single value as parameter like below
Post::find(1);
find() method also can accept array like below
Post::find([1,2]) // it selects id of 1 and 2 from posts tbl
find() method also can take second parameter where we can specify number of fields also so that less data is fetched from database server
Post::find([1,2], ['id','title']); // suppose posts tbl has id, user_id, title, description, created_at, updated_at