Hint: Firstly, you could describe what exactly an electric field is both quantitatively as well as qualitatively. Then, you could describe the possible ways in which we could detect the presence of electric fields in certain regions. Also, mention if there is some device with which we could detect them.
Complete answer: In the question, we are supposed to find how an electric field could be detected. Firstly, let us understand the concept of electric field. The concept of electric field was introduced by Michael Faraday. By definition, the electric field is the electric force per unit charge. It is the physical field that is found to surround the electric charge and is the manifestation of the electromagnetic force which is a fundamental force of nature. We know that any charge within the vicinity of an electric field will definitely experience a force. This force per unit charge will give us the value of the electric field. So, we could keep a unit charge of any sign of your choice and check whether this charge experiences any force on it. If yes, we could confirm that we have kept the charge within some electric field. In addition, we have an electric compass needle which is very similar to the magnetic compass needle which we are well aware of.
Note: Volts per meter is found to be the derived SI unit of an electric field. If q is the charge that we keep in the vicinity of an electric charge, then, the force experienced by this charge could be given by, $F=qE$ The SI unit is found to be newtons per coulomb.