Where To Change/remove This

The best way to customize that text is to use the following filter of the plugin:

add_filter('asp_stripe_payments_checkout_page_result', 'custom_stripe_checkout_output', 10, 2);

function custom_stripe_checkout_output($output, $post_data)
{
    //TODO create/add your customized text in the $output variable 

    //return the output variable so the plugin can show it
    return $output;
}

Alternatively, you can directly customize the plugin’s file that outputs that text. Look inside the following file:

stripe-payments/public/views/checkout.php