Legal Question in Family Law in Washington

There are no mandatory forms to do this. The best way is honestly to hire an attorney, or if you cannot afford one, to seek one pro bono for a step parent adoption.

During the process, you will need the biological mother to agree to relinquish her parental rights, or for the court to terminate her parental rights. If there is not agreement on this issue, it will be very difficult for you to get a court to terminate a parent's rights. There have to be serious and long term deficits for this to happen.

Assuming you have an agreement in place to adopt, you will also need a social worker to perform what's known as a pre and post placement report, essentially indicating that they have done the required due diligence to be able to say that you are an appropriate person to adopt your step-child.

Once all that is done, the adoption can go through. This is a very simplified overview of the process, but if gives you an idea of what is needed.