Email sync between iPhone and ipad

Nothing syncs between devices. They either sync to iCloud or to an email server e.e. Google, AOL, Exchange, Outlook, Yahoo or any Other. Please see the pic below

If Contacts were on iCloud, try this --> Restore contacts, calendars, bookmarks, and more using ...

For Contacts on other accounts --> Contacts on an iPhone, iPad & Mac - Apple Community

See any of the following:

• Calendar: Restore your calendars and events on iCloud.com
• Contacts: Restore contacts stored in iCloud on iCloud.com
• iCloud Drive, Pages, Numbers and Keynote: Recover deleted files on iCloud.com
• iCloud Photos: Delete and recover photos and videos on iCloud.com
• Mail: Delete email in Mail on iCloud.com
• Notes: Delete and recover notes on iCloud.com
• Reminders: Restore your reminders on iCloud.com
• Safari bookmarks and Reading List: Restore your Safari bookmarks and Reading List on iCloud.com

If you had turned on Messages in iCloud, iCloud Photos, Mail, Health data, call history under iCloud, and files you store in iCloud Drive your content is automatically stored in iCloud and is available on all devices that use the same Apple ID