Library services are the common document management functions for controlling the users with permissions to create multiple instances of a document (versioning) and the users with access a document to make changes (checking-in/out).
So far, you have learned about creating spaces, adding files, and editing them. You might have more than one person who can edit a document. What if somebody edits a document, and removes a useful piece of information? Well, you can use versioning features to avoid such issues.
Versioning allows history of previous versions of a content to be kept. Content needs to be versionable for versions to be kept. You can enable versioning in four different ways: