OK so Manjaro can’t detect your Windows (but OS Prober is properly enabled so in theory if everything is OK it should), because there is a mismatch EFI/MBR or because of something else, like maybe the fastboot setting in Windows, or some other oddity.
//EDIT: output of sudo fdisk -l?
Also check if you properly disabled fastboot in Windows. Check this thread for reference [root tip] [How To] Dual boot Manjaro and Windows