In most situations and places, parking violations can be reported online or on call. Traffic/parking enforcement authorities usually have a dedicated portal or a number for such reporting, or you may even contact your local police. When reporting a violation, it is important that you clearly understand and keep specific details handy, including the vehicle make, model, color, number, and vehicle condition. It is a good idea to take a picture of the illegally parked vehicle and take it such that the picture shows how the parking is illegal. You should also have a clear understanding of where exactly the vehicle is parked. Unless the violation is obvious, you may want to go over the parking regulations before taking action. Assumptions often do more harm than good, and you may then contact the relevant authority or submit a report online.