The correct sequence in data processing is input $\to$ process $\to$ output. This means that data is entered or collected (input), then it is processed or analyzed (process), and finally, the results are displayed or communicated (output).
For example, when a salesperson enters the details of a sale into a computer system (input), the system then calculates the total amount of the sale, updates the inventory, and generates an invoice (process). The invoice is then printed or sent to the customer (output).
It is important to follow this sequence to ensure that the data is accurate and the results are reliable.