What is the Xray Document Generator?
Xray Document Generator is a feature that allows you to customize your own templates and generate documents regarding your Jira data, mainly, Xray issues, requirements, and defects. It's easy to set up and start creating your documents.
Please check Curated list of Document Generator Templates to see some concrete examples of templates available out-of-the-box, ready to use or to customize.
There are also some useful Tutorials, Tips & Tricks for Document Generator and Xporter.