What does attesting to service of process mean in a legal document that was notarized?

My sister and I lost a sister and she didn't have any benificiaries on her life insurance...my step mom thought that she was the benificiary and is now trying to fight the insurance company to get the money. In fact they are not releasing funds because of no beneficiary..she then gave this piece of paper to my sister and I to sign and get notarized without telling us what it's about, her attorney then mailed us a letter saying Comes now Petitioner and files the affidavits of:me and sisters name attesting to service of process. Please help me with this...is she trying to get over on us