In Microsoft Fabric, Environments are used to define the Spark runtime, compute configurations, and, most importantly, the library packages (Python, R, etc.) for notebooks and Spark jobs.

To make a specific set of libraries available by default to all new notebooks within a workspace, you must first create an environment. Next, you install the required libraries into this newly created environment. Finally, you configure the workspace settings to set this environment as the default for the entire workspace. Once set, any new notebook or Spark job created in that workspace will automatically inherit this environment and have all its pre-installed libraries available.

Microsoft Fabric Documentation | "Manage Apache Spark libraries in Fabric": This document states, "To set default libraries, you have to be the administrator of the workspace. As admin, you can perform these tasks: Create a new environment. Install the required libraries in the environment. Attach this environment as the workspace default."

Microsoft Fabric Documentation | "Create, configure, and use an environment in Fabric": This document details the process of creating an environment and managing its settings, including the "Libraries" section for adding public or custom libraries.

Microsoft Fabric Documentation | "Workspace settings for Data Engineering and Data Science": This documentation explains how to set a default environment for a workspace. Under the "Spark settings" for the workspace, an administrator can select a specific environment to be the default, which will then be "automatically attached to notebooks" in that workspace.