Emailing from zoho - where do rejected emails go

Emailing from zoho - where do rejected emails go

Hi
 
When sending emails from Zoho, what happens to mails that are not able to be delivered due to an invalid email address?  Is there any method of finding out if the delivery was successfuly or not, or being able to identify which are rejected?
 
Any help or assistance would be greatly appreciated.
 
Thanks