> ## Documentation Index > Fetch the complete documentation index at: https://docs.aversure.com/llms.txt > Use this file to discover all available pages before exploring further. # Introduction to user rights > Overview of user groups, roles, and permissions in a data room A user is added to a data room by adding the user to one of the user groups of the data room. Initially, a data room is created with three user groups: **Administrator**, **Reader** and **Writer**. The **Administrator** user group has full privileges, which cannot be restricted. A user in the Administrator user group can add and remove users (including other administrators), edit permissions, and create new user groups. Only administrators are allowed to access a disabled data room. Initially, the **Reader** user group has permission to view and download all files in a data room, but no right to upload, edit, move or delete files. Initially, the **Writer** user group has permission to view, download, upload, edit, move and delete files in a data room. The Writer user group cannot add or remove users from a data room or edit any permissions. The rights of the Reader and Writer user groups can be [changed by administrators](/users-and-user-rights/customizing-user-rights). A user may only belong to a single user group within each data room. If a user is added to a new user group, they are removed from the old user group.