A group of Microsoft Products and technologies used for sharing and managing content, knowledge, and applications.
Hi Steve,
Thanks for posting back.
Normally, when you use the Search feature in SharePoint to search files, it will crawl related metadata of files, like Created Date. Yes, it can also search the content of SharePoint files while based on my test, it won't search all the contents of one file as accurately as the built-in search function of OneNote. If you want to search the keyword in one file, I think the built-in feature of Office applications is more suitable for your organization.
Also, if you want to manage result sources in SharePoint, please view the following reference.
Appreciate your understanding and patience.
Regards,
George