If you are using the Woocommerce Points and Rewards plugin, you can reward users for referring friends with points instead of a coupon. To do so, go to the Points and Rewards plugin settings and change the number of points under the “Points earned for referring a user”.
After that, if you want to stop generating coupons, add the code below to functions.php file:
add_filter( 'gens_raf_generate_coupon', '__return_false' );
And that’s it!