First, please contact the local parish in which you wish to be wed to find out whether it is possible. Some of our parishes serve an enormous number of parishioners and are unable to accommodate weddings for non-parishioners as a result. This policy is set by the parishes individually.
During your marriage preparation in your home diocese, your pastor will have put together a marriage file on your behalf. This will include, at minimum, the prenuptial investigation for the bride and groom, sacramental certificates, and sworn, notarized statements from other parties confirming your freedom to marry. This file will be sent first to the Chancery of the diocese in which you live, then to this office, and then to the parish in which the wedding is to take place.