To hide 'via Fee Total amount' in the Invoice document - By WebToffee ( WooCommerce PDF Invoices, Packing Slips, Delivery Notes, and Shipping Labels)

functions.php

<?php //do not copy this line of code
add_filter('wf_pklist_alter_find_replace','wf_pklist_alter_fee_details',10,6);
function wf_pklist_alter_fee_details($find_replace, $template_type, $order, $box_packing, $order_package, $html)
{
	if($template_type=='invoice')
	{
		$order_id = (WC()->version < '2.7.0') ? $order->id : $order->get_id();
		$user_currency=get_post_meta($order_id, '_order_currency', true);
		$fee_details=$order->get_items('fee');
        if(!empty($fee_details))
        {
			$fee_arr = array();
	        foreach($fee_details as $fee_detail)
	        {
				$fee_arr[] = wc_price($fee_detail['amount'],array('currency'=>$user_currency)).' via '.$fee_detail['name'];
			}
			$find_replace['[wfte_product_table_fee]']=implode('<br />', $fee_arr);
		}
		else
		{
			$find_replace['[wfte_product_table_fee]']='';
		}
	}
	return $find_replace;
}

Thank you. This worked.