Windows 8, 8.1 and 10 systems do not have user-accessible product keys. They are embedded in the system board and cannot be viewed or changed by users (only the manufacturer can do that). Activation happens automatically on first boot (and any time a valid OS is installed).
Bitlocker code is stored in OneDrive for Windows 8/8.1/10, if you've set it up that way. Bitlocker needs to be set up for it to work (so it won't be enabled on a new system), unless of course, you're using a PC that was set up for work/school and it has set policies.