To create residual income, you need to create something that people will continue to buy on a regular basis long after you’ve created it. A house is a prime example of this as people will continue to pay rent for the right to live in the house. A business needs to have products that are sold over and over again rather than trading the business owner’s time for money.
Residual income is the amount of net income generated in excess of the minimum rate of return. Residual income concepts have been used in a number of contexts, including as a measurement of internal corporate performance whereby a company's management team evaluates the return generated relative to the company's minimum required return. Alternatively, in personal finance, residual income is the level of income that an individual has after the deduction of all personal debts and expenses have been paid.