Which programming language first introduced 'Hello World' as a first program to code for beginners?
The history section of the Wikipedia article indicates it came from C.
...the tradition of using the phrase "Hello, world!" as a test message was influenced by an example program in the seminal book The C Programming Language. The example program from that book prints
"hello, world"(without capital letters or exclamation mark), and was inherited from a 1974 Bell Laboratories internal memorandum by Brian Kernighan, Programming in C: A Tutorial...
The convention was introduced for the general public in K&R - Kernigan and Richie: The C Programming Language - which is the canonical introduction to C. That book became the canonical because it was succinct reflecting in its thinness.
The updated version covering ANSI C is worth reading simply for their approach to writing documentation.