The carriage return and linefeed combo are the commands to move to the next line of a teletype. Other commands might (in theory) be used for this purpose on oth

The carriage return and linefeed combo are the commands to move to the next line of a teletype. Other commands might (in theory) be used for this purpose on other devices. These are implementation details. Text inside a computer doesn't need any of that just to signal a newline. UNIX chose to use a single line feed character as a line separator because there was no good reason to use two. MacOS chose a single carriage return for similar reasons. Anything going out to a printer or teletype would run through a device driver that would turn the newline character into whatever the device expects. Windows copied DOS which copied CP/M which was a very basic program loader for 8-bit machines and didn't really have "drivers" like we think of them today. I'm guessing here, but I imagine they chose the teletype combo because that's what most serial printers understood and printing was a major use case for those machines. That was probably the right choice for CP/M, but I can't imagine Microsoft would choose it if they were developing Windows from scratch today.