The canonically correct term is "Declaration of Invalidity," which is a judicial pronouncement that a marriage is invalid at the time of consent for various reasons. An annulment is exclusively religious in nature, focusing on the sacrament, and does not affect any legal proceedings.
Anyone who was previously married and is seeking to marry in the Catholic Church may need a declaration of invalidity of their first marriage.
You should see a priest, deacon or diocesan appointed advocate within the Diocese which you reside to begin the process. We encourage you to talk a to a priest that you are comfortable with.
The normal processing time in the Diocese of Houma-Thibodaux is 12 months from the time of acceptance of the petition by the Tribunal Office. This does not include the time that it takes to gather all the information (baptismal certificates, marriage certificates, divorce decree and testimony). The reason for the lengthy process is that each case is investigated very carefully and instructed according to the laws of the Church.
Absolutely not. Your marriage was entered into legally and the assumption of marriage in the Church was always present, thereby making any children born of the union legitimate.
If you are not remarried and are free of grave sin (requires confession), yes! However, if you have remarried outside of the church, your current marriage should be convalidated before receiving communion. This would mean that your first marriage would have to be determined invalid.
Yes, you may petition the Tribunal at any time once you have obtained a civil divorce. If a declaration of invalidity is granted, your church of baptism will have a notation of the annulment for future reference.