We manufacture Home Automation Products. Depending on sophistication we offer two solutions. Broadly this automation solution consists of Hardware and App (working on smart devices). This solution is suitable for single room. We will be charging Excise Duty on the Hardware Products, however, Apps are made available FREE OF COST on Apple, Android and Windows App stores. Since the Apps are given to the user Free of Cost, there is no financial transaction taking place. Hence we will not be making invoice either.. Query- not making invoice and not charging excise duty or service tax is legally correct from Excise and Service Tax point of view ?