Q: How do i delete my iMessage on my mac?

Your question is a bit vague so it's hard to know exactly what you are trying to accomplish.

If you're trying to remove the Messages application, it's locked by the operating system and cannot be removed.

If you want to sign out of iMessage.  Open Messages and select Messages from the menu bar then Preferences.  Go to the Accounts tab, select the iMessage account, then sign out.

If you want to delete all previous messages from the computer (this will affect all services that are used with Messages, not just iMessage)  Open Finder and go to ~/Library/Messages, drag all the contents to the trash.