How do I save what is on an logged in user account

I have and PHP website where yo are supposed to get coins develop a country but when the user clicks the Get more! button they get one more coin, and when they reload boom the coins are back at zero :frowning_face: :frowning_face: :frowning_face: I do not want this to happen any ideas how to do this I think I need MySQL and PHP again.

<?php
	echo <<<_END
	
<p>You have </p><a href="#" id="more" class="list-group-item disabled">0 </a>
<script>
function more(){
          let sum = document.getElementById("more").innerHTML
              sum++
              document.getElementById("more").innerHTML = sum
        }
		
</script>
_END;
	echo <<<_END
		<img src="coin.png" width="2%" alt="coins">
	_END;
	echo <<<_END
	<button onClick="more()">More!</button>//button to get more coins
	
	_END;
	
	?>

I am not sure if this is enough code to show you if not ask me for more and I will happily give it to you. :grinning: