Lets say you have url1.com and url2.com and you have url2.com showing up in url1.com in an iframe if you have target deployed on url2.com that is good and it will allow you to edit content on url2.com however in order to edit content on url1.com you will need to also have Target implemented there. Here is more on implementing Target: Implement Target overview
If this satisfies your query please like, mark as helpful and mark as answer. Otherwise lets keep the conversation going. Hope you have a wonderful day.