After post share buttons using functions.php

I’ve created a child theme at https://tinyhouserepoert.com and have installed the Social Share plugin rtShare.

I need to place the share buttons after the post content and to do that I need to add the php code ‘<?php if ( function_exists( ‘rtsocial’ ) ) { echo rtsocial(); } ?>’ to my functions.php.

So specifically I need to add a function to my functions.php that uses the above code to place it at the end of my post content.

Suggestions???