Unsure how to find out how to wipe my iPhone 8

Did you mean the passcode to "Open" your iPhone when you first turn it on? If YES then here is how to reset that passcode If you forgot the passcode for your iPhone, iPad, or iPod touch, or your device is disabled - Apple Support

Good Luck.

Axel F.

If you meant the restrictions (ScreenTime) passcode, use the same link that Axel provided. The procedure is the same. But, when done, DO NOT try to restore data from a backup, since that restrictions passcode comes back again.

Regards

Giulio