• The user submits the name of the domain or domains to be transferred to the new registrar.
• If an authorization or EPP key is required, the current registrar will send an email to the domain owner with the proper key. (Authorization keys are required for all tlds Arvixe handles: .com, .net., .org, etc.)
• Authorization key is provided to the new registrar.
• The domain transfer is submitted to the registry by the new registrar.
• An email is sent to the domain owner requesting for approval of the transfer process by the new registrar.
• The domain owner can either approve or disapprove the transfer request.
• If the request is approved, the transfer is completed. The transfer period varies between registrars, but it is estimated to be between 5 to 10 days.

• It is locked with your current registrar.
• Incorrect EPP/Authorization Key.
• You are transferring it to the same registrar it is registered with (yes this can happen sometimes).
• The name includes profanity (some registrars do not allow that).
• It is privately registered (the email wouldn’t get to the owner).
• The email address on file is not the most recent email (administrative contact email address is inaccessible).
• A domain name transfer is prohibited during the first 60 days of initial registration or during the first 60 days after a registrar transfer.
• The domain name has already expired.

5 to 10 days.

Yes, interms of .BD & .বাংলা domain its called domain ownership change. Please visit here for more details.