How do I sync my emails with mac, iphone and ipad.

That is easy if you are using Icloud email. See:

https://support.apple.com/en-gb/guide/icloud/mm6b1a17e3/icloud

If you are using any other email provider, you can only do it if you use mail apps on your devices to connect to your email providers email servers. You will need to connect to the mail servers using Imap with the same account details on all devices. Then if you delete an email - it will be deleted on the server, and all devices will see the same.

It might be possible for someone to give you more specific advice if you tell us what email service you are using.

Make sure your email account is an IMAP account and that it is set up as an IMAP account on each devices accessing the account.