The Windows Update Status icon in the taskbar notification area was first introduced in the Windows 10 April 2018 Update (version 1803).
By default, the Windows Update Status notification icon will only show on the taskbar when there is a warning or alert about Windows Update showing on the Settings > Update & Security > Windows Update page.
You can click/tap on the Windows Update Status icon to open the Settings > Update & Security > Windows Update page.
You can right click on the Windows Update Status icon, it will open a context menu to click/tap on available options. The available options will vary depending on what the warning or alert is for, but can be: Restart now, Schedule restart, Download now, Open Windows Update, and Hide for now.
If you prefer to not to see the Windows Update Status icon, you can disable it.
This tutorial will show you how to enable or disable the Windows Update Status icon in the taskbar notification area for your account or all users in Windows 10.