There are lots of courses ,PGDM PGPM, MBA, Executive MBA etc !! Please tell me the differences considering Placements ,What should I go for?

There is not much difference between PGDM and MBA in India. As per statute, only universities can grant degree and others can only provide the diploma. Till recent IIM Bill, IIMs also did not have the power to grant MBA, they used to provide PGDM. But in India, most respected management certificate is the PGDM certificate from IIM Ahmedabad. But there are rare cases where foreign universities ask for MBA for higher studies and do not accept PGDM. Your institutes matter more than the name of the degree.
Executive MBA is for people who have fixed years of experience according to the institute demand. PGDM courses consider as flagship programs of IIMs.
Normally you have to choose your electives at the end of the first year and for each specialization, you need a minimum number of credits according to institute policy. In IIM Raipur, as per placement rule, you need at least 5 electives from total 16 subjects in a particular specialization to sit for placement in that specialization. This means you may have multiple specializations. But for PSUs, you need 8 electives in respective specialization

PGDM and PGPM stand for Post Graduate Diploma in Management and Post Graduate Program in Management. They are diplomas that are offered by IIMs and other private MBA colleges that cannot award degrees since they arent under any university. It is similar to a MBA. A PGDM from an IIM has the same value as a MBA in the industry. So, PGDM, PGPM and MBA are the same things. Executive MBA is however different. It is what working professionals having more than 5 years of work experience pursue so that they can work and at the same time get a MBA. That being said yes of course you can apply for marketing and finance jobs both in colleges. Domain specialization is something that is not decided by the course you choose. When you opt for a PGDM course or a MBA you can specialize in any domain you want to at the end of two years. In order to specialize in marketing or finance you have to opt for certain subjects offered and fulfill a certain credit requirement in that domain.