There is no clipboard on iPhones (that can be seen) if I’m not mistaken, all it means is that you have copied the data and have to paste it somewhere. All iPhone come with a pre installed notes application. Click on the app and create a new note, once you have done that tap on the blinking icon (the little bar that indicates that you’re typing) and it will give you the option to paste. Hope this helps you out.
There is no clipboard to go to. It is in the background on your phone just like a computer. It is a temporary holding place. You can paste to notes, or in an email, or some other place where you can type.