That’s exactly what can be done for an easy installation. You only need one partition to install Manjaro in BIOS mode. Only, consider using a swap file then later-on.
You should place the bootloader into MBR. After executing
sudo update-grub
in your freshly installed Manjaro OS you can boot into Windoze from your grub menu. If your grub menu is not appearing you might need to modifiy the /etc/default/grub file a bit, but one step after another, see here: