Where can I get guardianship forms?

I want to get guardianship of my sister because her mother is on drugs again, never has money for pampers or anything she needs so when she need pampers or anything she comes to me or my grandma for it, and I just feel like my sister isn’t safe with her mother, so how can I get guardianship forms without going to court or goes through a lawyer?

UPDATE-

I took her for the night, she was sick for a month and the night I got her she throw up, and Saturday her grandma took her but Sunday I got her back and she was still sick so I took her to the hospital Monday and I told her mother and she never showed up I was there for 3 hours, but she is getting better the only thing is that she has a little cough