WooCommerce is great with security and I understand the importance of having the user check the “I have read and agree to the websites terms and conditions*” but sometimes you might just want to skip the extra step and help the customer along in their checkout process. This is what I’m going to explain how to do: How to pre-check the terms and conditions box on WooCommerce checkout.
After searching the google machine and some Stack Overflow, I found a very simple function that just needs to be added to your functions.php file. That code is located below
add_filter( 'woocommerce_terms_is_checked_default', '__return_true' );
That’s it. You may notice that the function takes a little while to run. While the checkout is loading the checkbox will be unchecked but once it finishes loading, it will check the box.
Here is the original source for the function above. It was posted in the comments by Rob Neu.