Anatomy of India's New GST Invoice Format

looks like you have customized the theme to ignore the headings.

but why do heading appears when using print buttton and disappears only when creating pdf using the button provided on the software ? any idea ??

following is the theme coding

<table style="padding: 20px 20px">
<thead>
    <tr>
        <td colspan="99">
            <table style="margin-bottom: 10px"><tr>
                <td style="font-weight: bold; font-size: 32px">{% if title != 'Invoice' %}{{ title }}{% endif %}{% if title == 'Invoice' %}{{ title | replace: "Invoice", "GST  Invoice" }}{% endif %}</td>
                {% if business.logo != null %}<td style="text-align: right"><img src="{{ business.logo }}" style="max-height: 100px; max-width: 300px"></td>{% endif %}
            </tr></table>
            
            <table style="margin-bottom: 20px"><tr>
                <td style="width: 200px; border-left-width: 5px; padding-left: 10px; text-align: left">
                    {% for field in fields %}
                    <div style="font-weight: bold; font-size: 12px">{{ field.label | replace: "Invoice date", " Invoice Date" | replace: "Invoice number", " Invoice No" | replace: "Order number", "Vehicle No"}}</div>
                    <div style="margin-bottom: 10px; font-weight: bold; font-size: 16px">{{ field.text }}</div>
                    {% endfor %}
                </td>
                {% if title == 'Invoice' %}
                <td style="width: 260px; padding-left: 20px; border-color: #000000; border-left-width: 1px">
                {% for field in custom_fields %}
                {% if field.label == "Shipped To:" %}{% continue %}{% endif %}
                {% if field.label == "Notes" %}{% continue %}{% endif %}
                {% if field.label == 'Total in words' %}{% continue %}{% endif %}
                <div style="font-size: 12px; padding-bottom: 10px"><b>{{ field.label }}</b> {{ field.text | newline_to_br }}</div>
                {% endfor %}</td>{% endif %}
                <td style="width: 300px; padding-left: 10px; padding-right: 5px; text-align: left; vertical-align: top; border-top-width: 3px; border-bottom-width: 5px">
                    <div style="text-align:LEFT;font-weight: bold;font-size: 18px">{{ business.name }}</div>
                    <div style="text-align:LEFT;font-size: 12px">{{ business.address | newline_to_br }}</div>
                    <div style="text-align:LEFT;font-weight: bold;font-size: 14px">{{ business.identifier }}</div>
                </td>
            </tr></table>
            <table style="margin-bottom: 20px">
            <td style="width: 380px; text-align: left; border-color: #000000; border-bottom-width: 2px; border-top-width: 2px; border-left-width: 2px; border-right-width: 2px">
                {% if title == 'Invoice' %}<div style="padding-left: 5px; border-bottom-width: 2px; text-align:LEFT;font-weight: bold">Billed To:</div>{% endif %}
                <div style="padding-left: 20px">
                <div><b>{{ recipient.name }}</b> {{ recipient.code }}</div>
                <div>{{ recipient.address | newline_to_br }}</div>
                <div><b>{{ recipient.identifier }}</b></div></div>
            </td>
            {% if title == 'Invoice' %}
                <td style="width: 375px; padding-left: 5px; text-align: left; border-color: #000000; border-bottom-width: 2px; border-top-width: 2px; border-left-width: 0px; border-right-width: 2px">
                    {% for field in custom_fields %}{% if field.label == 'Shipped To:' %}{% assign consignee = field.text %}
                    <div style="padding-left: 5px; border-bottom-width: 2px; text-align:LEFT;font-weight: bold">{{ field.label }}</div>
                    <div style="padding-left: 20px">{{ field.text | newline_to_br }}</div>
                    {% endif %}{% endfor %}
                    {% if consignee == null %}
                    <div style="padding-left: 5px; border-bottom-width: 2px; text-align:LEFT;font-weight: bold">Shipped To:</div>
                    <div style="padding-left: 20px">
                    <div><b>{{ recipient.name }}</b> {{ recipient.code }}</div>
                    <div>{{ recipient.address | newline_to_br }}</div>
                    <div><b>{{ recipient.identifier }}</b></div></div>{% endif %}
                </td>
            {% endif %}
            </table>

            <div style="font-size: 10px; font-weight: bold; margin-bottom: 20px">{{ description }}</div>
        
    </td></tr>
    
    <tr>
        <td style="width: 25px; font-weight: bold; padding: 5px 5px; border-bottom-width: 1px; border-left-width: 1px; border-top-width: 1px; text-align:CENTER">#</td>
        {% for column in table.columns %}            
        <td style="font-weight: bold; padding: 5px 10px; text-align: {{ column.align }}; border-left-width: 1px; border-bottom-width: 1px; border-top-width: 1px{% if forloop.last == true %}; border-right-width: 1px{% endif %}{% if column.nowrap %}; white-space: nowrap; width: 80px{% endif %}">{{ column.label }}</td>
        {% endfor %}
    </tr>
</thead>
<tbody>
    {% assign i = 0 %}
    {% for row in table.rows %}
    {% assign i = i | plus: 1 %}
    <tr>
        <td style="width: 25px; padding: 5px 5px; border-left-width: 1px; text-align:CENTER">{{ i }}</td>
        {% for cell in row.cells %}
        <td style="padding: 5px 10px; text-align: {{ table.columns[forloop.index0].align }}; border-left-width: 1px{% if forloop.last == true %}; border-right-width: 1px{% endif %}{% if table.columns[forloop.index0].nowrap %}; white-space: nowrap; width: 80px{% endif %}">{{ cell.text | newline_to_br }}</td>
        {% endfor %}
    </tr>
    {% endfor %}
    <tr>
    {% for column in table.columns %}            
        <td style="border-bottom-width: 1px; border-left-width: 1px{% if forloop.last == true %}; border-right-width: 1px{% endif %}"></td>
    {% endfor %}
    </tr>
    {% for total in table.totals %}
    <tr>
        <td colspan="{{ table.columns | size }}" style="padding: 5px 10px; text-align: right{% if total.emphasis == true %}; font-weight: bold{% endif %}">{{ total.label }}</td>
        <td style="border-left-width: 1px; white-space: nowrap; border-right-width: 1px; border-bottom-width: 1px; padding: 5px 10px; text-align: right{% if forloop.first == true %}; border-top-width: 1px{% endif %}{% if total.emphasis == true %}; font-weight: bold{% endif %}">{{ total.text }}</td>
    </tr>
    {% endfor %}
    <tr><td colspan="{{ table.columns | size | plus:1 }}" style="border-right-width: 1px; border-top-width: 1px; border-bottom-width: 1px; border-left-width: 1px"><div style="font-size: 12px; padding-left: 10px; padding-right: 10px; font-weight: bold">{% for field in custom_fields %}{% if field.label == 'Total in words' %}{{ field.text }} Only</div>{% endif %}{% endfor %}</td></tr>
    {% for field in custom_fields %}
    {% if title == 'Invoice' %}
    {% if field.label != "Notes" %}{% continue %}{% endif %}
    {% endif %}
    <tr>
        <td colspan="99">
            <div style="font-weight: bold; padding-top: 20px">{{ field.label }}</div>
            <div>{{ field.text | newline_to_br }}</div>
        </td>
    </tr>
    {% endfor %}
</tbody>
<tfoot>
<tr>
    {% if title == 'Invoice' %}
    <td colspan="99">
        <div style="text-align: right">Certified that the particulars given above are true & correct.</div><div style="text-align: right; font-weight: bold">For {{ business.name }}<br><br><br><br><br>Authorised Signatory</div></td>
    {% endif %}
</tr>
</tfoot>

please understand that this is not a coding forum.
if you do not have the skills to customize a theme personally please hire someone locally to do it for you.
only the official themes are supported in the forum.

ok thank you for the help