I was reading the document and thought this file was only available from the ISO file (as part of "Preparing to Install"), but I found it later just following the instruction 🙂
For one who does know about secure boot, I found this link What Is Secure Boot and How Does it Work?
PS: I have it enabled on mine now. Thank you
❯ bootctl status | grep "Secure Boot"
Couldn't find EFI system partition. It is recommended to mount it to /boot or /efi.
Alternatively, use --esp-path= to specify path to mount point.
Secure Boot: enabled (user)