To pick how many days of recent mail to synchronize with your account in iOS Mail:
- Tap Settings on the iOS Home_ screen.
- Select Mail, Contacts, Calendars.
- Tap the desired account under; Accounts
- Now tap Mail Days to Sync.
- Pick how many recent days’ mail you want to be sent to iPhone Mail automatically.
- Choose No Limit to synchronize all mail.
Note: These instructions are for older versions of iOS