If the “View optional updates” link is missing from Windows Update is because at that specific time there’s not new updates available for your device. Windows 10 will continue to check your device and once a new update becomes available the option will be visible in the Settings app.
Optional updates are those updates that are not critical to use Windows 10, but they may be necessary for other functionalities. These updates can include packages for Microsoft and non-Microsoft products, feature updates, and third-party drivers (such as for GPU, printers, cameras, and network adapters).
In the case that you need to update a device driver, then you should check the device manufacturer page to download and install the latest version using their instructions.