The Dell service tag is a seven character identifier that is unique to your product. In addition to the service tag, there is an Express Service Code which is a 10-digit numeric version of the service tag which can be typed into a telephone for call routing. While most Dell products have a service tag, some accessories and peripherals do not. As a general rule, desktop and notebook computers, servers and storage devices, printers, and mobile devices (such as phones or tablets) will have a service tag.
Desktop computer systems include these model names: Dimension, Inspiron, Optiplex, XPS, Vostro, Alienware, and Precision Workstation.
The service tag label will probably be located on the back of the computer case, but can also be located on the top or side of the system.
Some computer cases have an access panel on the front. The service tag label can usually be found behind the panel door.