syncing mail between Apple devices - iPad, iphone, and laptop

We apologize for our mistake, radishonastick.

We’d like for you to remove the email accounts from your devices and add them back again. This willl make sure that everything is set up correctly again:

Add and remove email accounts on iPhone - Apple Support

Add and remove email accounts on iPad - Apple Support

Log out of or remove email accounts in Mail on Mac - Apple Support

Add email accounts in Mail on Mac - Apple Support

Once the accounts have been removed, restart all three devices and add the accounts again.

Please let us know the results when you're able.

All the best.

Hi radishonastick,

Thanks for contacting Apple Support Communities!

We understand that when your email messages are deleted from one device, the changes don't appear on another device, correct?

Are you using iCloud mail or a different email service?

If you're using iCloud, this article includes helpful troubleshooting steps for the iPhone, iPad and Mac with iCloud Mail: If iCloud Mail isn't working - Apple Support

"Things to check first

1. Check the system status of iCloud Mail.
2. Check that you turned on iCloud Mail:

• On your Mac, open the Mail app then choose Mail >Preferences. Click Accounts, then select your iCloud account in the sidebar. Under Account Information, make sure that the account is turned on and the status is online. 
• On your iPhone, iPad, or iPod touch, go to Settings > [your name] > iCloud and check that Mail is turned on. 

1. Make sure you that haven't exceeded your iCloud storage limit. If you exceed your iCloud storage limit, learn how to make more space available in iCloud. 
2. Make sure that you're using the latest version of software on your device. "

We hope this helps.

Cheers!

If using an IMAP mailbox as you have indicated, all your mail messages are kept on your email providers mail server - a copy being downloaded to your Mail App.

While deletion of the mail account from your iPad will also remove the currently downloaded copies of your mail, the actual mail remains available on the mail server.

When you re-add the mail account, your Mail App will re-synchronise with the mail server - and again download a copy of mail messages that are stored in your mail account.

As such, removal of an IMAP mail account from your iPad will have absolutely no impact upon mail stored on the mail server.