First make sure you do want to dual boot. Virtual machines these days are pretty good and close to hardware, can often to speak 3d hardware, can speak to USB and much more besides. https://www.virtualbox.org/ being where most start here.
Deleting one then is then as easy as deleting a file and uninstalling a program, you can transfer them to new systems trivially, and get back into the host machine as easy as switching programs.
Beyond that most things that come as a live CD/USB/whatever will have a means to install them on the machine.
You typically make a space on the drive or maybe have another in the machine. Making space tends to mean you change the partition sizes (might need a tool like gparted, if you don't know what you are doing here you can mess up the drive) to free up enough for the new partitions say Linux will want (can be as few as one, three or four is more normal). You need not make the new partitions yourself -- if you just have the main partition shrunk then the live CD/installer should have some decent suggestions.
The would be live CD should install some kind of dual boot as part of it all. For some more security focused computers you might also have to go into the BIOS to allow it. Equally some of the older implementations of such things might not deal with the new boots
There are a vanishingly small number of live operating systems that will install all their files and operate from a NTFS (Windows) formatted drive, though some of those are some of the more notable versions of Linux. Most would be wary of doing this as there are things that can get tricky (fail to shut down Windows properly and the drive might be read only until you load Windows again to have it reset, not a problem if you are reading files from a dead computer or something but hardware if you are trying to work an OS)
If you are on Windows primarily and editing things I have always liked/used easybcd to avoid hassle with such things. https://neosmart.net/EasyBCD/
"Live OS" is normally referring to loading an OS directly from a CD/DVD or USB, which you can already do easily by just inserting it and selecting the corresponding option in the boot menu.
I assume you mean you want to install it. That usually just works as long as you have free unpartitioned space before starting up the installer, and you install Linux (or whatever else) *after* installing Windows, since Windows will overwrite the boot manager and the Windows boot manager can only load Windows.
And as FAST6191 said you can resize the drive to make room, however Windows will not let you resize the Windows partition IIRC, so you have to use another tool to do so.
I think Ubuntu these days allows you to install it as a file on the Windows partition, so your partitioning stays the same, but read/write speeds will suffer somewhat, since it's not directly accessing a partition on the drive but has to go through extra steps. Other than that it should be fully functional. But it's not the recommended way of doing things.
There is no install option, but I only wanted to install since I didn't want to have a flash drive sticking out, but there is a copy to RAM option! The Live OS is made to just connect to another server, and that's it. I wonder if I can change the default keyboard layout and put my login info in the boot drive so I don't have to log in every time.
You need the installable ISO image if you intend to install it, not a live OS, if you want to install it on the same HDD as your Windows OS, just create another partition and install it on that or use another HDD, Virtualization is another option that you can consider if you don't want to mess up your bootable C drive.