Microsoft authenticator can not sync to another device

hi, i would like to ask about my authenticator application for sync to another. i have changed a new iphone recently, and i can not move my old app code to the new phone. i am sure i already opened icloud sync function. at the same time, i remembered when i downloaded authenticator on my new phone will appear a button for transfer before. but now its disappeared. i had no idea right now. looking forward to your reply. best regards.