Hello Atul Dighe,
Thanks for your question.
To use authenticator on a new phone you have to load up the old backup of the authenticator. If you did not back it up to the cloud or werent able to transfer data before switching phones you would need contact the admins of the accounts in question for work or school accounts if you do not have recovery methods.
You can also contact the support teams of any applications to assist you in resetting your credentials or reach out to support https://support.microsoft.com/en-us/topic/customer-service-phone-numbers-c0389ade-5640-e588-8b0e-28de8afeb3f2
You can mark it 'Accept Answer' and 'Upvote' if this helped you
Regards,
Abiola