The XML Editor is a convenient way to edit your XML documents. If your XML Document has a corresponding XML schema that describes it, then you can make use of intellisense and more complete validation.
If your document does not reference a schema explicitly, then you can associate one with it see Associating a schema with your XML Document.
If you don't have a schema, then you can infer one from your sample document and use that, see Inferring and XML Schema (XSD).
|If you are using the Visual Studio Plug-in, then the standard XML Editor is used. See Microsoft documentation for this.
Also see Associating a schema with an XML Document in Visual Studio