woocommerce signup form addons

1)add extra fields in woocommerce

function wooc_extra_register_fields() {?>
       <p class="form-row form-row-wide">
       <label for="reg_billing_phone"><?php _e( 'Phone', 'woocommerce' ); ?></label>
       <input type="text" class="input-text" name="billing_phone" id="reg_billing_phone" value="<?php esc_attr_e( $_POST['billing_phone'] ); ?>" />
       </p>
       <p class="form-row form-row-first">
       <label for="reg_billing_first_name"><?php _e( 'First name', 'woocommerce' ); ?><span class="required">*</span></label>
       <input type="text" class="input-text" name="billing_first_name" id="reg_billing_first_name" value="<?php if ( ! empty( $_POST['billing_first_name'] ) ) esc_attr_e( $_POST['billing_first_name'] ); ?>" />
       </p>
       <p class="form-row form-row-last">
       <label for="reg_billing_last_name"><?php _e( 'Last name', 'woocommerce' ); ?><span class="required">*</span></label>
       <input type="text" class="input-text" name="billing_last_name" id="reg_billing_last_name" value="<?php if ( ! empty( $_POST['billing_last_name'] ) ) esc_attr_e( $_POST['billing_last_name'] ); ?>" />
       </p>
       <div class="clear"></div>
       <?php
 }
 add_action( 'woocommerce_register_form_start', 'wooc_extra_register_fields' );

2)validate fields

/**

* register fields Validating.

*/

function wooc_validate_extra_register_fields( $username, $email, $validation_errors ) {

      if ( isset( $_POST['billing_first_name'] ) && empty( $_POST['billing_first_name'] ) ) {

             $validation_errors->add( 'billing_first_name_error', __( '<strong>Error</strong>: First name is required!', 'woocommerce' ) );

      }

      if ( isset( $_POST['billing_last_name'] ) && empty( $_POST['billing_last_name'] ) ) {

             $validation_errors->add( 'billing_last_name_error', __( '<strong>Error</strong>: Last name is required!.', 'woocommerce' ) );

      }
         return $validation_errors;
}

add_action( 'woocommerce_register_post', 'wooc_validate_extra_register_fields', 10, 3 );

3) save values to database

/**
* Below code save extra fields.
*/
function wooc_save_extra_register_fields( $customer_id ) {
    if ( isset( $_POST['billing_phone'] ) ) {
                 // Phone input filed which is used in WooCommerce
                 update_user_meta( $customer_id, 'billing_phone', sanitize_text_field( $_POST['billing_phone'] ) );
          }
      if ( isset( $_POST['billing_first_name'] ) ) {
             //First name field which is by default
             update_user_meta( $customer_id, 'first_name', sanitize_text_field( $_POST['billing_first_name'] ) );
             // First name field which is used in WooCommerce
             update_user_meta( $customer_id, 'billing_first_name', sanitize_text_field( $_POST['billing_first_name'] ) );
      }
      if ( isset( $_POST['billing_last_name'] ) ) {
             // Last name field which is by default
             update_user_meta( $customer_id, 'last_name', sanitize_text_field( $_POST['billing_last_name'] ) );
             // Last name field which is used in WooCommerce
             update_user_meta( $customer_id, 'billing_last_name', sanitize_text_field( $_POST['billing_last_name'] ) );
      }

}
add_action( 'woocommerce_created_customer', 'wooc_save_extra_register_fields' );