Adoption requires a legal process which is dependent on your geographical location in the world. It could be done through an agency, internationally, independently, and so on.
It is true that a lot of times, parents adopt a child when they do not have a biological child that they can call their own. However, a point often overlooked is that child adoption is not only for parents who cannot have their own biological child. It is also for parents who already have a child and are financially secure. Furthermore, it is for parents who feel the need to help another child have a family and a better life.
For this reason, parents who are financially capable are encouraged to adopt a child and give him or her, an opportunity to have a family and a brighter future.
Annie Watson