Dear! Your questions is not very clear enough, but as far as I can gather, your wife has expired and she had properties in her name for which you require a legal heir certifcate. If it is so, then you are required to apply for the same in the court of the district judge only of the district where the properties are situated. You may even have to go to other revenue officers like Tehsildar aur Taluqdar of a village.
The officers hand over a form which must be correctly and completely filled. The person making such application must carry the requisite documents and stamp fees must be paid. If the person belongs to SC/ST category, then he does not require to pay this stamp fee. The form must be submitted by Family Lawyers to the officer, after which an enquiry takes place. The inspection is conducted by the Revenue Inspector as well as Village Administrative Officer. Once the enquiry is successfully completed, the legal heirship certificate is issued.
If the case is otherwise, please provide the information on the same so that I can answer it correctly. :-)
Also, in India we used to stay with my parents at my permanent address in Mumbai. However my wife was from Delhi and all her identification documents have the address of her place Delhi.
Do we need to get the certificate from Mumbai or Delhi?
Firstly you have to obtain the LHC from the competent court ( District Court of Delhi) where she had all her documents. You will have to furnish the documents which will disclose the relationship between the deceased and her legal heirs. Then you will have to send the LHC, obtained from the Indian court to Qatar where she was working, with all other documents that the office requires from you. That should hopefully suffice. Good Luck!