In an agency adoption, the birth mother signs something called a “relinquishment,” which terminates her parental rights, and makes the adoption agency the legal custodian of the child. The agency then places the child for adoption with an appropriate adopting family.
Although these days, most agencies will allow the birth mother some input into what family is selected, it is still the agency, not the birth mother, who is placing the child for adoption.
In an independent adoption, the birth mother selects the adopting family personally, and places her child with that family personally, without an agency being involved in the process. Instead of signing a “relinquishment,” she signs something different called a “consent,” which does not terminate her parental rights, but does indicate her permission for the adopting family to adopt the child.
In recent years, a number of agencies have begun offering a hybrid adoption, which has many of the attributes of both agency and independent adoption, and these are often referred to as “identified adoptions,” or “collaborative adoptions.”