BIOS passwords cannot be recovered. If you have forgotten one of the passwords that is set in the BIOS, resetting the CMOS or NVRAM helps reset the BIOS to factory default settings and remove the passwords from the BIOS. WARNING: Clearing the CMOS or NVRAM using a jumper resets the passwords in the BIOS.
https://www.dell.com/support/kbdoc/en-us/000131024/how-to-clear-the-bios-password