Using Copy, Paste On iPhone
There are couple of ways you can use copy and paste on the iPhone and iPod Touch
Double tap a word, the word should now be highlighted lightly in blue and there will also be a little blue dot on each end of the word. You can copy that word by pressing the Copy button, or touch and drag the blue little dots to highlight even more words to copy. To paste what you just copied, double tap again and the Paste option will come up.
Touch and hold on a word until a magnifying glass appears then let go. You will get the option to Select the word or Select All. The blue dot option will appear after your selection as well. To paste your text just do any of the following methods and you will get a Paste option.