There are two primary types of document management systems: cloud-based and on-premise.
Cloud-based document management solutions are hosted by third-party companies and store all user data in their own cloud servers. The provider maintains security and the infrastructure of the DMS, but users have access to their documents at any time through an app or the web.
On-premise document management systems are managed and operated by businesses themselves. They use their own local servers and infrastructure to store documents, putting all security and management of the DMS onto themselves.