Modules can be thought of as installable extensions to Alfresco. Once packaged into an AMP file format they can be applied to Alfresco using the Module Management Tool (MMT). Alfresco has two directories that contain AMP files, the amps directory and the amps_share directory. Modules that extend the repository tier are located in the amps directory. Modules that extend the Share tier are located in the amps_share directory.
When a module is installed using the MMT it is applied to the relevant WAR file. The Alfresco application typically consists of at least two WAR files: alfresco.war for the content server and share.war for the web client. The module AMP file is applied to the appropriate WAR using the MMT.
Larger, more complex modules can be distributed as two AMP files, one to be applied to the Alfresco WAR file and another to be applied to the Share WAR file. Records Management, for example, is distributed in this manner.