getElementsByTagName()

js/script.js

function funMake() {
document.getElementsByTagName('p')[0].innerHTML = 'Hello World!';
document.getElementsByTagName('p')[1].innerHTML = 'Привет Мир!';
document.getElementsByTagName('p')[2].innerHTML = 'To be or not to be?';
}

function funMake() {
document.getElementsByTagName('p')[0].innerHTML = 'Hello World!';
document.getElementsByTagName('p')[1].innerHTML = 'Привет Мир!';
document.getElementsByTagName('p')[2].innerHTML = 'To be or not to be?';
}

index.html

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>New Page</title>
<script src="js/script.js"></script>
</head>
<body>
<p></p>
<p></p>
<p></p>
<script>
funMake();
</script>
</body>
</html>

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>New Page</title>
<script src="js/script.js"></script>
</head>
<body>
<p></p>
<p></p>
<p></p>
<script>
funMake();
</script>
</body>
</html>