Headless Documents
A Headless Document represents a typical web-page - very similar to standard Pimcore documents.
Once the template configuration is ready, Headless Documents can be added as any other document by selecting the Headless Document template in document tree context menu:
Working with Headless Documents is similar to working with other document types as the same principles apply. They are like documents with a very simple template.
Change Template
In the settings of a Headless Document it is possible to change the template. But be careful, that might mean loss of the current content of the document.