In order to generate a Product Data Feed in the XML format you need to specify some attributes that will be displayed for each product in the Data Feed. To specify those attributes you need to go to your store Administration Panel -- M1 Export Tools -- Advanced XML Export. Please find "Customizable Fields" section and "Product Nodes" line in it.

Select some product-related Database fields from a dropdown (can be something like product_name or product_id). This is where unique data for each product will be taken from. Then enter a corresponding Product Attribute name (can be name for product_name or id for product_id).

You can see an example of how product attributes should be defined below:

Click Update or Update and Generate button when finished. Then you can check your Generated file if it looks the way you expect it to. If not -you can always come back and change the Product nodes according to your needs.