It depends very much on the service provider.

When you receive a message, it's a copy of the original message the sender wrote. The sender might keep a copy of it or they might not.

The server that sent the message on might also keep a copy, or not.

The email on your computer or phone is usually another copy downloaded from your mail service.

Deleting an email you received will usually move it to a separate trash folder so you can get it back if you change your mind. The mail service you're using may also have its own similar function so they can recover deleted messages even if you empty your own trash.

Also, the person who sent the email can delete their copy, and it goes to their recycle/trash bin. And the service they use probably has the same thing.

Also, there may be backups of any of these systems, each with a copy of your message.

So deleting an email in one place does not necessarily delete it everywhere.