You can do using this way –
This template can be overridden by copying it to yourtheme/woocommerce/emails/plain/email-order-details.php
if ( $sent_to_admin ) {
/* translators: %s: Order link. */
echo "\n" . sprintf( esc_html__( 'View order: %s', 'woocommerce' ), esc_url( $order->get_edit_order_url() ) ) . "\n";
}