We start by creating a variable that contains all the elements with the classname of 'year'
Then we go through each one and change its 'Inner HTML' to the text of the 'full current year' (eg. 2022).
The code can be pasted on any page's 'Before </body> tag' or on the site's settings 'Footer code'.
<script>
var yearElements = document.getElementsByClassName( 'year' );
[].slice.call(yearElements).forEach(function (div) {
div.innerHTML = new Date().getFullYear();
});
</script>
Whenever possible, use Class Names to target the elements in your interaction. You never know when you'll need to duplicate and use it somewhere else...