Automatic update notification
No special steps are needed to update Home Assistant Voice Preview Edition. If a new software version is available, you will see a notification in Home Assistant, like with any other update.
I receive no automatic update notification
You will not receive the device firmware updates automatically if you took control of the device in the ESPHome Device Builder add-on because you wanted to customize the device further. You will still be able to benefit from updates by recompiling your device.
Unless you have a good reason, don’t take control of the device in the ESPHome Device Builder add-on.