Up until twenty years ago, artists recorded their album in an expensive 24-track studio. Demos were made at home with a 4-track recorder or reel-to-reel, and their quality was "lo-fi" at best. Musicians still record in the studio and demos are still being made on 4-track cassettes, but hiring an expensive studio and sound engineer is no longer required.
Thanks to the arrival of (external) audio interfaces, recording at home has become very easy, fast ánd inexpensive. All you need to get started is a computer, audio interface, microphone (or an alternative), and DAW-software (Cubase, Pro Tools, Reason, Ableton Live) - you get a free basic version of DAW-software with the purchase of an audio interface. 1-2-3-4-5-7-8, go!