Different invoice name for different customer group (OC.3.0.3.1)

I have a question. I have 2 different customer group.

And i want different invoice title. Example:

Customer group1: Invoice

Customer group2: Pre-Invoice

Oc 3.0.3.1 Thanks for help. Im very beginner.

Do this step by step

Changes : 1

File Path : admin\controller\sale\order.php

Find

'voucher'          => $voucher_data,

After ADD Below Code

'customer_group'   => $order_info['customer_group_id'],

Changes : 2

File Path : admin\view\template\sale\order_invoice.twig

Find

<h1>{{ text_invoice }} #{{ order.order_id }}</h1>

Replace Below Code

{% if order.customer_group == '2' %}
    <h1>Pre-Invoice #{{ order.order_id }}</h1>
{% else %}
    <h1>Invoice #{{ order.order_id }}</h1>
{% endif %}

OUTPUT :