You can save the current page you are viewing using Save Page As. Either:

• Ctrl+S
• menu button > Save Page As...
• right-click a blank area of the page > Save Page As...

This doesn't always work the first time, and even when you choose the "complete" option it might not be complete. Sometimes it work better to print to PDF or use the screenshot feature.

Best is usually to verify that you get the full page, especially if content is loaded via JavaScript in the background and images loaded lazily or via CSS.