How long does it take for a social security acceptance letter to arrive after it is mailed there?

How long does it take for a social security acceptance letter to arrive after it has been mailed there? According to the query related public information shows that the social security transfer to the general need for sixty days to the account, by the insured person to the new place of social security agency, put forward a written application for the transfer of relations. Within 15 working days, the social security agency in the new place of participation will review and approve the application for transfer. Within 15 working days after the original organization receives the letter of acceptance, it will complete the transfer procedures. Notification within 15 working days after completion.