What is a summons?
A summons is a formal order that you need to appear in court at a specific time and date in order to respond to either a civil lawsuit or criminal charges that have been brought against you. If you receive a summons, you must respond to the summons in some manner. If you do not respond to the summons, then a bench warrant may be issued for your arrest if the summons was for criminal charges, or a judgment in favor of the plaintiff may be automatically issued.
A summons must be sent in a specific manner, depending on the requirements of your state and the type of summons that you are sent. Generally, this means that the summons has to be given to you personally (referred to as personal service of process) unless you waive personal service. In some instances, as long as the summons is signed for by an agent authorized to act for you that will be sufficient. If the summons is not sent properly, then it may not be legally valid, so make sure you talk to a lawyer and explain all the details about how and when the documents were received.
Assuming the summons was served properly, the exact procedure for how you will respond may vary. You may need to file an answer to the summons- your own legal documents- and include any cross claims or other motions that you may want to make before coming to court. You may also just have to show up at court on a certain date.
Regardless of the specific type of summons, you will want to consult with a lawyer as soon as you receive one in order to ensure that you respond to it properly and don't do anything to jeopardize your legal rights.