Check VFS website for more info on D type of visa. VFS is the agency that is handling all visa applications to Belgium.
Indeed the paperwork is quite big, but pretty straightforward.
From my experience, below are the things that comes to my mind which you may need to apply for D type visa.
1. Original work permit that your employer will send to you after securing it from the authorities here
2. Medical certificate (legalized I guess - VFS does the legalization). If you are in Bangalore, St Johns hospital (Madiwala) is the authorized hospital to give you a medical certificate for Belgian visa application. If you call them and say you need medical check for Belgian visa application, they will guide you further with securing an appointment for it. They do this frequently and know the process and format of the certificate, etc.
3. Police Clearance Certificate (PCC) from India: Â Â [If you have lived in any other country in the last 1 year, you may need PCC from that country too) - This must be apostiled by MEA. You will find many agents who can help you with apostile process. VFS also has aspostile service.
4. Medical Insurance - (or an undertaking letter from your employer stating that they will subscribe you to medical insurance when you are here)
5. Proof of accommodation - Booking reference of Initial stay when you arrive here and a letter stating you will (or your employer will assist you to) find a long term accommodation during your initial stay.
6. Signed work contract & offer letter in original.
7. Duly filled Schengen visa application form - You can download from VFS website the latest form.
8. Your original passport - Valid for at least 12 more months, with at least 2 adjacent blank pages.
9. Processing Fees: You may have to pay visa application handling fee in VFS in local currency. Additionally, as per new process, there is an additional administrative fee of 215 EUR or so, have to be paid to the Belgian immigration office (Part of the Internal Affairs Service) prior to your visa D application. This must be paid in Euros. More info here:
10. Photographs (specifications available in VFS website)
Note:
- Filled form and all documents - you need to make 2 copies of everything to submit the application. One original and two photocopies of everything.
- If you are moving with your spouse and child, there are additional documents you must collect.
Important: What I listed is from my experience and what I could gather. VFS website is the source of truth. If you have questions, feel free to visit VFS office or call them.
Hope this helps..
EDIT: Processing fee or handling fee may have changed or become obsolete with the new single permit process. Consult your consulate or VFS for latest info.