Explanation:

Basically, the realization concept derives from the recognition revenue principle. In accounting, we recognize the revenue from sale of goods or provision of services when such goods are delivered or the services are rendered to customers. In this case, upon the delivery of goods or services, the revenues both from the provision of goods or services is said to be realized.
The realization concept is that the revenue is recognized and recorded in the period in which they are realized; similarly to accrual basis accounting. In similar term, we realize as revenues when we deliver the agreed product with customers or the services have been rendered to them.