I have a cell in a tableView, with a button I want to add an action to.
The button will be an email address. When the button is pressed, I want to trigger a delegate
You cannot pass anything into a target's action method. You don't call the method; the target-action architecture calls it when the button is tapped. The action method must take one parameter, namely the sender (which in this case will be the button).
If the action method needs more information at the time that it is called, you must provide that information in some other way, e.g. as an instance property that the action method can access when it is called.