Hi, I'm Bernard. I'm happy to help!
Are you the only one signed in to that device, or is there a previous owner of the PC? If there is, you need to ask the previous owner for the BitLocker key, or direct them to the link below.
If you are the only one, or there is another account on it, go to:
https://account.microsoft.com/devices/recoverykey
To check for the BitLocker recovery key.
For reference: https://support.microsoft.com/en-us/windows/find-your-bitlocker-recovery-key-6b71ad27-0b89-ea08-f143-056f5ab347d6