To change the system sounds on Windows 11, use these steps:

1. Open Settings.

2. Click on Personalization.

3. Click the Themes page on the right side.

4. Click the Sounds option.

5. Click the Sounds tab (if applicable).

6. Select the event to change the sound under the "Program Events" section.

7. (Optional) Click the Test button to preview it.

8. Select the preferred sound with the "Sounds" menu.

9. Repeat steps 6 through 7 to change other system sounds.

10. Click the Apply button.

11. Click the OK button.

Once you complete the steps, the new sounds for the system events will apply on Windows 11.