If you are sending your parcels outside of the European Union then a customs form must be attached to your parcel. Each country has their own set of regulations when items outside are sent to the country, if you are sending a gift then please check on the country‘s customs website to see how much you can send.
For instance in Japan, you can send a gift value of up to 10,000 yen. Gifts under 1,000 RMB in China are exempt from duties and tax.
As with every country, you can send most things but please bear in mind that prohibited/restricted items are not permitted.