Check with the parish priest where the wedding is to be held, who is responsible to see that the required documents are present.

Always you will need these three :

a) Baptismal certificate; of recent date; from your native parish
b) Pre-Nuptial Enquiry Form (by a priest of your parish)
c) Letter of Freedom (or Affidavit)

Usually these also :

d) Certificate from a pre-marriage course
e) A Confirmation certificate
f) Licence from the bride's parish (to wed elsewhere)
g) Document from your local registrar (ROI only).

If marrying abroad, your wedding papers go to your wedding church-venue via your local bishop's office.