Do I HAVE to file for child support?

Yesterday a friend got upset with me because she found out I wasn't threatening my child's father for child support. I am NOT on Medicaid. My friend is, and in order for her to stay on Medicaid and receive child care she had to file for child support. My daughter is on Medicaid and her dad isn't on her birth certificate. Because of that I couldn't legally put his information down when I put her on Medicaid. Since then Medicaid HAS NOT asked for his information. My question is, do i have to file? He doesn't have a job so I know the payments won't be much. I will also soon have a job where my daughter can go on my own insurance plan, so she won't need Medicaid for much longer. I work a job right now, but it doesn't offer insurance for her. So my question is, do I have to file for child support? I haven't read anywhere in her plan that says i have to do that, and since I don't have government child care or Medicaid for myself, is it fine?