The Texas courts adopted Rule 21a which allows a party to serve official court documents via email. The email address of an attorney or unrepresented party who electronically files a document must be included on the document.A Respondent in a Texas lawsuit may, under certain circumstances, be served through their social media accounts or via their email address. This is sometimes called "service of citation" or "service of process. " It is legal notice to the other side that you have filed your case. This is sometimes called "service of citation" or "service of process. " It is legal notice to the other side that you have filed your case. This is called substituted service. The respondent will not have to sign anything. See Texas Rules of Civil Procedure Rule 106(a)(1).