Unfortunately - marriage entries for that period contain very little really useful info which may help to advance your research.
Fathers names were not shown on marriage entries prior to 1.7.1837 which is the date when Civil Registration was introduced. Mothers names are never shown on English marriage certs
You can see the full transcription here
www.lan-opc.org.ukMarriage: 22 Sep 1821 St Anne Richmond, Liverpool, Lancashire, England
Benjamin Roberts - Accountant of Liverpool
Ann Baldwin - Spinister of same Parish
Witness: H. T. Hewitt; Edwd. Roberts
Married by Licence by: David Hewitt Officiating Minister
Register: Marriages 1816 - 1822, Page 262, Entry 1939
Source: LDS Film 1656150
The original image shows they both signed the register