Bangladesh transit visa requirements depend on the route
Start with your flight route and the reason you need to transit Bangladesh.
A simple airside connection can be different from a journey where you need to clear immigration, collect baggage, change airports or stay in Bangladesh before the next flight. Your nationality and final destination can also matter.
Start with the complete itinerary. If a transit visa is required, the application should show the arrival, connection, onward departure and final destination clearly.
Before applying: Confirm whether your exact passport and itinerary require a Bangladesh transit visa. A private consultancy cannot replace an airline, immigration authority or Bangladesh mission decision.
Documents that may be relevant
Depending on current official requirements, useful evidence can include the passport, online application printout, photographs, confirmed or planned onward itinerary, destination-country entry permission where applicable, and an explanation of why entry into Bangladesh is needed during the connection.