Power of attorney, the right kind of bank account, and how to register a purchase without flying home — plus the parts you cannot delegate.
Buying from abroad is routine, but three things need arranging before you commit, and each takes longer than people expect.
Someone who can sign for you. A power of attorney lets a person in Bangladesh act on your behalf. It must be executed at the Bangladesh mission in your country and then stamped and registered at home before anyone will accept it. Give this weeks, not days, and name a person you would trust with the whole purchase price — because that is effectively what you are doing.
The right account. Sending money through formal banking channels, into an account in your own name, is what lets you take proceeds out again if you sell later. Money that arrives informally is difficult to trace back to you when it matters. Your bank will tell you which account type applies to your situation.
Documents certified in advance. Passport, proof of residence abroad, and the attested photographs and signatures the registration office will ask for. Getting a document certified once you are back in the country and out of leave is a bad week.
What you cannot delegate is the judgement. Have your own lawyer — chosen by you, paid by you — verify the land documents, and ask for photographs of the actual site with a recognisable landmark in frame. Not a rendering.