Let's be honest. There are too many different tools for managing content in Salesforce. There's Files. There's Salesforce CRM Content. There's Salesforce Knowledge. There's Salesforce Documents. And not to be left out - there's also Attachments to take into consideration. In this lesson we discuss the various options available to you as an admin on the platform.
Differences Between Files, Salesforce CRM Content, Salesforce Knowledge, Documents, and Attachments - https://help.salesforce.com/articleView?id=collab_files_differences.htm&type=5