Hide Tax Code Column

This how to hide column Tax in custom Themes

{% assign taxColumnIdx = -1 %}
{% for col in table.columns %}
    {% if col.label == 'Tax' %}
        {% assign taxColumnIdx = forloop.index0 %}
        {% break %}
    {% endif %}
{% endfor %}

{% assign mins = 1 %}
{% if taxColumnIdx != -1 %} {% assign mins = 2 %} {% endif %} 

<!-- column Header -->
{% for column in table.columns %}
    {% if forloop.index0 != taxColumnIdx %}
        <td >{{ column.label }}</td>
    {% endif %}
{% endfor %}

<!-- Cells Rows -->
{% for row in table.rows %}
<tr>
    {% for cell in row.cells %}
        {% if forloop.index0 != taxColumnIdx %}
            <td >{{ cell.text | newline_to_br }}</td>
        {% endif %}
    {% endfor %}
</tr>
{% endfor %}

<!-- Spacer Row -->
{% for column in table.columns %}
    {% if forloop.index0 != taxColumnIdx %}
        <td>&nbsp;</td>
    {% endif %}
{% endfor %}

<!-- Total Rows -->
{% for total in table.totals %}
    <tr>
        <td colspan="{{ table.columns | size | minus: mins }}">{{ total.label }}</td>
        <td>{{ total.text }}</td>
    </tr>
{% endfor %}

But it seems like your problem (Zimbabwean) is that when Tax Amount is zero or empty, the Tax and Tax Amount columns are not exposed in custom themes. Even though you have checked the Show tax amount column on the Invoice Form.

It seems that only developer @lubos can help you with this problem.