Thank you for answer. So, if my custom field have name x_card_number the code were:

<div class='client-detail'>
    <span class='label'>Card Number</span> 
    <t t-if='partner.x_card_number'>
        <span class='detail client-custom-field'><t t-esc='partner.x_card_number' /></span>
    </t>
    <t t-if='!partner.x_card_number'>
        <span class='detail client-custom-field empty'>N/A</span>
    </t>
</div>

Hi Link,

To add the custom field value to the Customer view from POS screen,  you can can add following code to pos->static-> src-> xml -> pos.xml, or you can add it  by extending the same template.

Thank You

<div class='client-detail'>
    <span class='label'>Test</span>
    <t t-if='partner.custom_field'>
        <span class='detail client-custom-field'><t t-esc='partner.custom_field' /></span>
    </t>
    <t t-if='!partner.custom_field'>
        <span class='detail client-custom-field empty'>N/A</span>
    </t>
</div>