To display seconds on the Windows 11 taskbar clock, you’ll need to resort to using third-party software or edit the Windows Registry because, as of my knowledge cutoff in early 2023, Windows 11 does not natively support showing seconds on the system clock in the taskbar. If you feel comfortable editing the Registry, here’s how:

1. Press `Windows Key + R` to open the Run dialog box.
2. Type `regedit` and press Enter to open the Registry Editor.
3. Navigate to `HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced`.
4. Right-click on the `Advanced` key, select New > DWORD (32-bit) Value.
5. Name this new value `ShowSecondsInSystemClock`.
6. Double-click on the new value and set its data to `1`.
7. Click OK to save your changes and close the Registry Editor.
8. Restart your computer for the changes to take effect.

After your computer restarts, you should see the second displayed on your taskbar clock.

Please bear in mind that editing the registry can be risky if not done correctly. If you’re not comfortable doing this or prefer a simpler solution, you might want to search for third-party applications that offer this feature with a user-friendly interface.

Always back up your registry before making any changes and proceed only if you understand the risks involved.