The documentation export feature will create a single HTML page that includes all documentation currently being displayed (example). Please note that diagrams with a perspective enabled with not be interactive (you'll be missing the tooltips), and the graph visualisation will be excluded entirely from the export. When viewing documentation, click the "Export to offline HTML page" link.
This feature will not work if popups are blocked, so please ensure that popups are allowed for
*.structurizr.com (or your on-premises/Lite installation) in your web browser.
Automating the export
Documentation is rendered client-side (i.e. in your web browser), so an automated export is only possible using a web browser in conjunction with an automation framework, for example headless Chrome and Puppeteer. See Help - Scripting API for more details, and the structurizr-puppeteer repo on GitHub has a pre-built script.