MBA/PGDM

Both PGDM and MBA are similar degrees with nomenclature difference. You are advised to select between both MBA and PGDM based on B-School ranking not name of degree. You may refer to following link for list of top MBA or PGDM B-Schools in India: https://www.shiksha.com/mba/ranking/top-mba-colleges-in-india/2-2-0-0-0

No, it never provides the same value except top 50 institutes, other full time MBA programmes also have no value as neither it helps in placement nor the organisation asking for MBA prefer students beyond this point as the ranking goes down placement also decreases. You should think for a part time MBA only after gaining minimum 3 years of work experience.

Yes, GMAT is mandatory and along with GMAT you have to have at least 3 years of work organisation in an organisation and also need to have minimum 6.5 IELTS score and at least a 4 years Bachelor's degree such as engineering or a Master's degree with good academic record.