Hi , I am vivek Sharma. I handle overseas projects and also involved in SEM projects. Pay Per Click or PPC advertising comes under the SEM Marketing. Search Engine Marketing is now a days very common marketing strategy which proves to be useful if you are in a instant search of customers for your business.
SEM is a mixture of both SEO and PPC advertising , or in other words SEO is just a module of SEM. When marketing is achieved through any digital marketing tool , it comes under this section only.