Have the donor write and sign a statement that he gives up all parental rights and responsibilities. Do not accept money from the donor to raise the child. Limit the donor's ability to visit the child. If you do use a known donor, and if you don't want him to be considered the legal father, have a doctor perform or oversee the insemination. This is very important.
Most state laws concerning a donor's legal status are valid only if a doctor was involved.
Using a doctor as the intermediary makes it easier for a court to decide that your donor is not a legal father. If you do want the donor to be considered a legal father, put his name in that space. Don't put your partner's name in that space without consulting a lawyer. It's not legal unless a court does it. It's important to remember that parenting law is different in every state, and that lesbian and gay family law is changing quickly.