BitLocker can provide a secure backup of the recovery key before starting protection. The recovery key can be found in several places, depending on the selection made when starting BitLocker and more definition BitLocker is a Windows encryption technology that protects your data from unauthorized access by encrypting your drive and requiring one or more confirmations before opening it.
Here is the link for you to check the BitLocker where and how can get:
Finding your BitLocker recovery key in Windows (microsoft.com)
Be mindful that without this BitLocker Key incase may happened to you for the computer system being ask for the BitLocker Key and you do not know. Click the link above and if you could not find the BitLocker Key, it means only that the data are no way to recover. The data are loss if that is happen. So be careful and have check it now what is your BitLocker Key.