How to add an field from user account into checkout page - php

Question

I want to add a field from user account into checkout fields in woocommerce. I have already a field "EU VAT Number" with its values for each user in account. I want to display this field and its value after billing details on checkout page.
I created a filter, but it displayw only the Field label with no value.
Below is my code
// Display a custom field on checkout and on My account > edit
billing address
add_filter( 'woocommerce_billing_fields' ,
'adding_billing_eu_vat_number', 20, 1 );
$vat = get_field('billing_eu_vat_number',
'user_'.get_current_user_id());
if( $vat = get_field( 'billing_eu_vat_number',
'user_'.get_current_user_id() ) ) { echo "<h3
style='margin:0;font-weight: 600;'>" . 'EU VAT NUMBER: ' .
$vat . '</h3>' ; }
function adding_billing_eu_vat_number ( $fields ) {
$fields['eu_vat_number'] = array(
'label' => __('EU VAT Number', 'woocommerce'),
'placeholder' => _x($vat, 'placeholder', 'woocommerce'),
'class' => array('form-row-wide'),
'required' => true,
'clear' => true,
);
return $fields;
}
I need each customer not to insert each time he order the eu vat number and to be already inserted.
Thank you in advance!

Answer 1

You need to give it a default value,
Try this
add_filter( 'woocommerce_billing_fields' , 'adding_billing_eu_vat_number', 20, 1 );
function adding_billing_eu_vat_number ( $fields ) {
$eu_vat_number = get_field('billing_eu_vat_number', 'user_'.get_current_user_id());
$fields['eu_vat_number'] = array(
'label' => __('EU VAT Number', 'woocommerce'),
'placeholder' => _x($vat, 'placeholder', 'woocommerce'),
'class' => array('form-row-wide'),
'required' => true,
'clear' => true,
'default' => $eu_vat_number;
);
return $fields;
}