Use the “File -> Save Workspace As …” to save it into a file.
Normally, you would only want to use a <name>.code-workspace file with multi-root projects (that is, projects that include multiple folders), but this is also the only way to rename a workspace.
More information:
- What is a workspace in vscode?
- Saving workspaces
P.S. All the credit goes to Henry for pointing me to .code-workspace files 🙂 Thanks!