Navigate to Services >Add New in your WordPress admin sidebar. And follow the screenshot for add new service post
Title: Give your post title in title field.
Content: Give your content in content area which goes to your post details body.
Services Category: Add your service category if need
Banner Background Image: You can upload background image from the option.
Featured Image: This image for service post card.
Custom Posts Custom Link: Here used two types of link. Post Details Page and Custom Link.
the others areas are also for services details.
In elementor edit mode you can control your services post (i.e: filter posts category wise) following the below screenshot