A friend has given me Alcatel phone I have factory reset the hole phone while trying to set it up it’s coming up with previous pin but friend can’t remover it how can I unlock it
Welcome to Android Central! If your friend doesn't know the PIN, then either they forgot it, or they also weren't the original owner. The phone is useless to you if you can't contact the original owner of the phone to help you unlock it. This is Factory Reset Protection, and is there to discourage people from stealing phones and making it their own.
The "stealing the phone and making it your own" being the key phrase here. Without the original owners pin/Google account password the phone is a brick. That's why it's so important for folks to make sure the phone has been truly unlocked by the previous owner before buying or acquiring it. That's how Google keeps our personal information safe