My iPad Pro does not sync mail with my iPhone. Help

Mail messages are not directly synchronised between devices. Instead, your email accounts have to be configured on each of your devices - each device retrieving email from the email server.

For IMAP mailboxes, the server effectively maintains the “master copy” of your email. Each mail client downloads a copy of the email messages, duplicating the folder structure as seen on the mail server. As email messages are read/moved/deleted, the server is updated; other mail clients accessing the mailbox synchronise their downloaded content.

POP3 mailboxes work slightly differently, however, all mail content is still individually downloaded by each client.

Ensure that you have added your email account(s) to each of devices:

Add an email account to your iPhone, iPad, or iPod touch - Apple Support

If you have already added your email account(s) to all your devices, if you still have problems, the easiest method to resolve an issue will require that your delete the related account from the device upon which you have the problem - and then re-add the account.

To delete an account from a device:

Settings > Mail > Accounts > [Your email account] > Delete Account

After deleting an account, a restart is recommended:

Force restart iPad (models with Face ID or with Touch ID in the top button)

If your iPad doesn’t have the Home button, do the following:

1. Press and quickly release the volume button nearest to the top button.
2. Press and quickly release the volume button farthest from the top button.
3. Press and hold the top button.
4. When the Apple logo appears, release the top button.

Force restart iPad (models with the Home button)

Press and hold the top button and the Home button at the same time. When the Apple logo appears, release both buttons.

After restarting the iPad, re-add the email account(s) as required.

We are being asked to guess your email service provider, as well as the type of email communication your account uses. This latter information may be visible at Settings > Mail > Accounts > [this account] > Account > Advanced. Do you see an acronym like IMAP or POP anywhere there?