For add custom fields in woocommerce use following code in your current themes functions.php file.

‘custom_text_field_title’,
‘label’ => __( ‘Custom Text Field Title’, ‘cfwc’ ),
‘class’ => ‘cfwc-custom-field’,
‘desc_tip’ => true,
‘description’ => __( ‘Enter the title of your custom text field.’, ‘ctwc’ ),
);
woocommerce_wp_text_input( $args );
}

//Save custom field
add_action( ‘woocommerce_process_product_meta’, ‘wc_save_custom_field’ );

function wc_save_custom_field( $post_id ) {
$product = wc_get_product( $post_id );
$title = isset( $_POST[‘custom_text_field_title’] ) ? $_POST[‘custom_text_field_title’] : ”;
$product->update_meta_data( ‘custom_text_field_title’, sanitize_text_field( $title ) );
$product->save();
}

?>

This will display at admin product page.

ID );
$title = $product->get_meta( ‘custom_text_field_title’ );
if( $title ) {
printf(
‘

‘,
esc_html( $title )
);
}
}

?>

This will display at single Product Page.

session->set( ‘custom_text_field_title’, $custom_item );
}
return $cart_item_data;
}

?>

__( “Custom text”, “woocommerce” ), “value” => $cart_item[‘custom_text_field_title’] );
}
return $custom_items;
}

?>

This will display at Cart and Checkout Page.

This will display at order received and admin order Page.