First of all, let me point out that I assist with annulment preparations at a parish level. Skeptic92 has already provided correct information, so I will just elaborate on this topic a bit more.
When a Catholic gets married, even if it is to a non-Catholic, the following requirements are set down by the Catholic Church:
- Appropriate pre-marriage instructions and testimonies/interviews.
- Wedding takes place inside a church building, chapel, etc.
- The couple expresses consent and exchanges vows in front of a Catholic priest, deacon or bishop.
- Two other witness are present when the couple expresses consent and exchanges vows.
Any deviation from this requires formal permission from the local Catholic bishop. Furthermore, a Catholic cannot marry a non-Catholic without formal permission from his/her bishop.
Deviation from just one of these requirements can (and almost certainly does) prevent the marriage from being valid.
All Catholics are bound by these requirements, even if they are unaware of them. The only Catholics who are not bound by them are those who have defected from the Catholic Church. The Church now has a very precise understanding what it means for a Catholic to defect. Simply being a non-practicing Catholic does not equate defection (at least not in terms of obligations to follow canon law).
Based on the little bit of information you posted, it sounds like your friend got married to a non-Catholic without her bishop’s permission, and likewise got married in a courthouse without her bishop’s permission (bishop’s normally do not permit a courthouse wedding unless the local law requires it). Therefore, this certainly seems like an invalid marriage.
Nevertheless, the Catholic Church presumes all marriages to be valid unless demonstrated otherwise, and that means an annulment investigation by a Catholic tribunal. What we are probably talking about here is called a “Lack of Form” annulment. Of all the different types of annulments in the Church, this is the fastest and easiest to obtain, because it deals with easily obtainable facts. For example, your friend either had her bishop’s permission or not. No permission = no validity.
But a civil divorce is also required. The Church does not believe that a civil divorce has the power to dissolve the sacramental bond of marriage, but the issue at hand is both a spiritual one and a legal one. When people get married, even if it is invalid, they form a legal bond to one another. If a marriage is annulled, the Church is officially declaring that the person is completely free to marry someone else. Being completely free includes the legal ties of the former marriage being dissolved, and this is done through a civil divorce proceeding. Therefore, part of the paperwork a tribunal requires in order to start an annulment investigation is a copy of a finalized divorce decree.
There are many other details and nuances that go into this sort of thing. Your friend should talk to her pastor. He is the one who will go over all this with her, give her the correct paperwork, and help her along in the process.