Workspaces are handy because you can create one of them for each project and change any setting or extension in VS Code at the Workspace level.

Creating a workspace

Open what you are working on

File > Save workspace as

This creates a *.code-workspace file that you can use to open your Workspace again in the future, and also serves as a config file that can be handy.

Adding other folders to a workspace

File > Add folder to workspace

For full details see: https://code.visualstudio.com/docs/editor/multi-root-workspaces