SIGNATUREFIN on a credit report: finance company loan
SIGNATUREFIN is probably a loan from a finance company: it runs a name, "SIGNATURE", into "FIN", the usual abbreviation for finance or financial.
How to find out which company reported SIGNATUREFIN
Your free report at AnnualCreditReport.com shows the full name and address of whoever reported SIGNATUREFIN; our guide to identifying a creditor covers the other ways to find out.