You need to turn of fast boot in Windows. You need to turn of TPM and Secure boot in UEFI ( what some people still but incorrectly call BIOS ) to install Ubuntu. You can install Ubuntu ( or another .iso ) if you install e.g. Grub2Win and make it your primairy bootloader. You need to add the option to boot from .iso in the bootmenu.
Then when booting choose the .iso.