Welcome to the forum.
Please note my corrections above. If you start a letter with "Dear Sir", you should finish with "Yours faithfully". If you start with "Dear + name", end with "Yours sincerely". Are you certain that the person you are writing to is male? If so, but you don't know his name, "Dear Sir" is OK. If you're not sure of their gender, use "Dear Sir/Madam" or "To Whom It May Concern" (although this isn't used much these days). In my opinion, you're more likely to get help if you find out the person's name and address the letter to them personally, ie "Dear Mr Jones/Dear Ms Jackson".
I have no idea what an "iagma transfer request" is, so I have left it as it is.

Interested in Language