Show Custom Fields in POSInvoice

I added a custom field named “tariff” in sales invoice
it’s showing in Standard view of Print Format
but i am not able to see it in POS invoice

how should i customise POSinvocie to show my custom field

POS print formats are manually coded.

<style>
	.print-format table, .print-format tr, 
	.print-format td, .print-format div, .print-format p {
		font-family: Monospace;
		line-height: 200%;
		vertical-align: middle;
	}
	@media screen {
		.print-format {
			width: 4in;
			padding: 0.25in;
			min-height: 8in;
		}
	}
</style>

<p class="text-center">
	{{ company }}<br>
	{{  __("POS No : ") }}{{offline_pos_name}}<br>
</p>
<p>
	<b>{{ __("Date") }}:</b> {{ dateutil.global_date_format(posting_date) }}<br>
</p>

<hr>
<table class="table table-condensed cart no-border">
	<thead>
		<tr>
			<th width="50%">{{ __("Item") }}</b></th>
			<th width="25%" class="text-right">{{ __("Qty") }}</th>
			<th width="25%" class="text-right">{{ __("Amount") }}</th>
		</tr>
	</thead>
	<tbody>
		{% for item in items %}
		<tr>
			<td>
				{{ item.item_name }}
			</td>
			<td class="text-right">{{ format_number(item.qty, precision("difference")) }}<br>@ {{ format_currency(item.rate, currency) }}</td>
			<td class="text-right">{{ format_currency(item.amount, currency) }}</td>
		</tr>
		{% endfor %}
	</tbody>
</table>

<table class="table table-condensed no-border">
	<tbody>
		<tr>
			<td class="text-right" style="width: 70%">
				{{ __("Net Total") }}
			</td>
			<td class="text-right">
				{{ format_currency(total, currency) }}
			</td>
		</tr>
		{% for row in taxes %}
		{% if not row.included_in_print_rate %}
		<tr>
			<td class="text-right" style="width: 70%">
				{{ row.description }}
			</td>
			<td class="text-right">
				{{ format_currency(row.tax_amount, currency) }}
			</td>
		</tr>
		{% endif %}
		{% endfor %}
		{% if discount_amount %}
		<tr>
			<td class="text-right" style="width: 75%">
				{{ __("Discount") }}
			</td>
			<td class="text-right">
				{{ format_currency(discount_amount, currency) }}
			</td>
		</tr>
		{% endif %}
		<tr>
			<td class="text-right" style="width: 75%">
				<b>{{ __("Grand Total") }}</b>
			</td>
			<td class="text-right">
				{{ format_currency(grand_total, currency) }}
			</td>
		</tr>
		<tr>
			<td class="text-right" style="width: 75%">
				<b>{{ __("Paid Amount") }}</b>
			</td>
			<td class="text-right">
				{{ format_currency(paid_amount, currency) }}
			</td>
		</tr>
	</tbody>
</table>


<hr>
<p>{{ terms }}</p>
<p class="text-center">{{ __("Thank you, please visit again.") }}</p>

You will have to learn how to modify this HTML to add your custom field.

Also this is called ‘Point of Sale’, located in Setup -->Print format