forname is your first name and any other names that come before your last (family) name.
If by this you mean what is the written style for priests and nuns in the Catholic church then it is as follows. Nuns - Sister Mother Superior - Reverend Mother Monk - Brother Abbot - Father Abbot Seminarian - First name Deacon - Deacon or most usually their forename. Priest - Father 'forename' or Father 'Surname'. Monsignor - Monsignor 'forname' or Monsignor 'Surname' Canon - Canon 'forename' or Canon 'surname'. Bishop - My Lord, Bishop 'forename' or Bishop 'Surname'. Archbishop - Your Grace. Patriarch - Your Beatitude Papal Nuncio - Your Excellency Cardinal - Your Eminence Pope - Your Holiness, Holy Father, Most Holy Father. Eastern Catholic clergy Sister - Sister 'forename' Abbess - Very Reverend Abbess Deacon - Father, Father Deacon Priest - Father 'forename' Archpriest - Father Bishop - Your Grace Archbishop - Your Emminence Metropolitan - Your Beatitude Patriarch - Your Beatitude Note that this is the style in English speaking countries but there may be some variation within non-english speaking countries.
In Irish:There are several options: Eilís [elleesh], Lís [leesh] all from Elizabeth.The native Irish name Laoise [leesha] might be substituted.Another name might be Sibéal [shibael].In Scottish Gaelic, Elizabeth is Ealasaid[yallusetch].It could also be Lisa: many Gaelic-speakers do not 'translate' their first names even when using their Gaelic surname.