@mmbb110 - Yes, it will be in the HTML code for the email you would have received in your Inbox. For email clients like Gmail, "Show original" option will provide the html code

@mmbb110- See the below links - https://experienceleague.adobe.com/docs/campaign-standard/using/working-with-apis/managing-workflows/triggering-a-signal-activity.html?lang=en#working-with-apishttps://experienceleague.adobe.com/docs/campaign-standard-learn/tutorials/managing-processes-and-data/execut...

Its an image of 0x0 pixel. you can find it in the source of the email received from campaign.

There is no api to do this in one go, but there are options like creating a workflow with signal activity that reads email address as parameter from your API call and deletes the record. Also note the limitations for triggering workflows via APIs