Journal requires to cite Arxiv pre-print of the same work – where and how do I cite?
Add something like this to your "Introduction" section:


  This paper has been published as an arxiv pre-print&lt;cite pre-print here&gt;


This is the approach I used when I published part of the research I had done for my thesis. It conveys the necessary information without cluttering the paper with verbiage that a majority of readers will find irrelevant.