How and where do you get an export licence in northeastern india-meghalaya?

You can get export licence through DGFT (Directorate general of foreign trade) office.
You can download the application form from their website at free of cost.
Attach required documents and fill the form without any mistake then submit to the DGFT office with a demand draft of Rs. 250/-.

Shillong DGFT office address and telephone number given below..

The Dy. Director General of Foreign Trade,
Morello Building,
Shillong - 793 001 Tel: 0361-223360
Fax: 0361-223360
E-Mail: shilong-dgft@nic.in