The concept of bookmarking a page is a feature of the browser. This is really outside the scope of what Selenium was created for.
That said, you can create a test which is equivalent to bookmarking. If we look at how saving a bookmark work, it saves the current URL. Using a bookmark is just taking the saved bookmark and pasting it into the address bar. In Selenium we have the following:'
String bookmark = driver.getCurrentUrl();
To use this bookmark would then be:
driver.get(bookmark);
So if you have a test case where you have to save a bookmark you can use the above code. If you need to use that bookmark then you can use the second piece of code. If using this works and we assume the browser's bookmark feature works then it would be a pass.