How edit the ‘Fee’ line in WooCommerce emails

If I add a fee to an order and send an invoice, the amount of the fee appears before the word ‘fee’ in the invoice email, followed by the amount of the fee. For example, if I add a $45 fee, the fee line appears as:

$45.00 fee: $45.00

Where can I edit this line so it just says ‘Fee: $45.00’

Thanks.