Tournaments or cash? A dilemma for the ages! But in reality, it's not such a difficult choice. If you are completely new to poker, then I would suggest that you try to play both, to understand what is more suitable for you personally.
If you are familiar with both formats, but can not decide, and are serious about becoming a professional in this game, making it your main source of income, then I would still recommend you to play cash. The income in the cache is stable and relatively predictable, and you will be able to manage your time normally.
But you should understand that good money can be made in any of the formats. Personally, I play both, but the main thing for me is still the tournament.