A passive income is an extra amount of money you can earn by doing little if any extra work in addition to your regular job. Here are some examples:
If you design your own app for a smartphone, you will earn money every time someone downloads it. A successful app can earn you a lot of money.
Many online writers are paid for the first few years that they write articles. Thereafter, they earn money based on page views of their articles. Well-written articles earn good money.
Create a YouTube video
You can run ads on a successful YouTube video. If your video goes viral, you stand to earn a lot of money.
Write a book
The author of a published book earns money from the sale of their book. Pitch your book to publishers, or you can self-publish an e-book.
You can sell photos you have taken to sites such as Shutterstock and earn a commission each time your image is downloaded.
Invest in the stock market
This should be approached with caution. Educate yourself thoroughly before entering the stock market.