To pay the tariff is a duty. When the post comes in your country. There is a possibility that the envelope may be taxed. In this case, you will be contacted by the company shipped. Because you may have to pay taxes prior to delivery to the intended recipient. If you don't pay taxes (which prices may vary in each country) that envelope will be destroyed.
In some countries, you will have to pay import duties (less than 15 USD) before delivery of the envelope
In this case, the shipping company will contact you by telephone number that you contact us.
If you don't pay taxes, post will be destroyed.