<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>innerHTML</title>
</head>
<body>
<h1>Exaple, "<span id="txt"></span>"</h1>
<input type="text" id="input">
<button onclick=" document.getElementById('txt').innerHTML = yourInput.value;">click me to change</button>
<script>
let yourInput = document.getElementById('input');
//this will get your wanted element and asing its value to let variable
</script>
</body>
</html>