desperate_one,
<!DOCTYPE HTML>
<html>
<head>
<title>Untitled</title>
<style type="text/css">
</style>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>
<script>
$(document).ready(function() {
$('.btns').click( function(event){
event.preventDefault();
$('#receiver').text($(this).siblings('.parent').find('h3').text())
})
})
</script>
</head>
<body>
<div id="root_parent">
<div class="parent">
<div class="header">
<h3>Text1</h3>
</div>
</div>
<div class="btns">
<button></button>
</div>
</div>
<div id="root_parent">
<div class="parent">
<div class="header">
<h3>Text2</h3>
</div>
</div>
<div class="btns">
<button></button>
</div>
</div>
<div id="root_parent">
<div class="parent">
<div class="header">
<h3>Text3</h3>
</div>
</div>
<div class="btns">
<button></button>
</div>
</div>
<div id="receiver">text</div>
</body>
</html>