It is hard to be sure exactly when Karaoke was invented, since the idea of playing background music without the vocalist, and very often of using another voice in its place, has been around almost as long as sound recordings have existed. People have done this for their own entertainment, or sometimes to save money, eg using the music as backing for a performer rather than paying for live musicians.
Something very similar to karaoke was practised in the USA in the early 1960s, with a TV show that played music with a chorus to sing the words, and showed the lyrics as subtitles on the screen, so audiences could sing along.
It is not sure who invented the karaoke machine itself, though it does seem to be Japanese in origin and may well have been the work of a musician, Daisuke Inoue, in 1971. In any case, it spread rapidly and by the early 1980s was well known throughout Japan. Today it is popular all over the world.