What is a citation? It is the additional document the clerks make to send with the original petition for service.
What does it do? Among other things, a citation lays out the rights a defendant to a lawsuit has, the answer day, the parties, and that if the defendant fails to respond, a default judgment could be entered against him.
Why is it important? Well, mainly because it is required under Texas law. And if it is wrong, the defendant can have a default judgment overturned. That’s time and money wasted.
An example? Well, in Heike Curley v. Michael Curley, 2014 WL 3867798, a defendant was served in a divorce case that involved children. Unfortunately, the citation used did not have the children listed. The defendant failed to answer, and a default was entered. The defendant then was able to overturn the default on appeal because of the defective citation.
The take away? Make sure your citations are correct. It is on you, not the court, because if a default is entered on a defective citation, and then the defendant files the appeal, there is going to be a new trial.