Passive income is a myth. Everything takes work. The only truly passive income comes in two forms:
1. Doing what you love - This is still work, but it just doesn't seem like it because you enjoy what you are doing.
2. Collecting off investments - The operative word here is investments, meaning you put a lot of work up front to reap benefits during the future when you work less. Even investments like stocks, savings accounts, and real estate require initial work (i.e. research, initial capital, etc.) and a modicum of ongoing work (i.e. general maintenance, ongoing monitoring, etc.).
That's not to say these are bad options, and there are certainly easiER ways to make money than a 9-5 or in addition to a 9-5. Just find something you like to do as a hobby, then monetize it in your sparetime (i.e. writing, art, buying/selling, etc.)