If you have a cause of action against more than one corporation and the causes of action are related, you need to include all of the corporations in one civil complaint. If you do not name them all, you may lose the right to sue those that you do not name. You can name as many related corporations as necessary in a complaint.
Read the rules of civil procedure for the jurisdiction in which you are filing a complaint, with particular attention to the rules for service of process. You can find rules for most states and federal courts available online on a government website or in a library.
Type the name of the court at the top of document.
Type your name on the left-hand side of the document under the court's name. Under your name, type "Plaintiff."
Skip two lines in the document. Press the tab key twice. Type "v." including the period. Skip two lines.
Type the name of the first corporation followed by a semi-colon. Type the name of the second corporation followed by a semi-colon. Repeat until all corporations are named. Under the last corporate name, type "Defendants." Different courts have different conventions for captioning complaints, but generally, they are similar: Name of Court Your Name, Plaintiff, v. Corporation 1; Corporation 2; Corporation 3, Defendants.
Write the legal causes of action that you have against all of the corporations in your complaint, including the court's jurisdiction over the corporations. Sign and notarize your complaint.
File your complaint with the clerk of the court. Take a copy for each corporation you named in the complaint and have the clerk file-stamp each copy.
Serve each corporation you named in the complaint with a file-stamped copy of the complaint according to the rules for service of process in your jurisdiction. Corporations are usually required to have an agent registered with the secretary of state who is served on behalf of the corporation.