Add an extra field to PowerPack's Registration Form module

functions.php

<?php // <-- ignore this line.

// Add new fields.
add_filter( 'pp_rf_fields', function( $fields, $settings, $id ) {
    if ( isset( $fields['consent'] ) ) {
        $consent = $fields['consent'];
        unset( $fields['consent'] );
    }

    // Register your fields here.
    $fields[] = array(
        'type' => 'text', // field type.
        'name' => 'company_name', // field name/slug.
        'label' => 'Company Name', // field label.
        'placeholder' => 'Company Name', // field placeholder.
    );

    if ( isset( $consent ) ) {
        $fields['consent'] = $consent;
    }

    return $fields;
}, 10, 3 );

// Logic to store the custom field value to the user meta.
add_action( 'pp_rf_user_register', function( $user_id, $data, $settings ) {
    if ( isset( $data['company_name'] ) ) {
        // Validate the field. You can add any additional validation here.
        $company_name = sanitize_text_field( $data['company_name'] );
        // Store the value.
        update_user_meta( $user_id, 'company_name', $company_name );
    }
}, 10, 3 );