Many carriers in English speaking countries, including FedEx and UPS, require the full ship to address - including the full country name - appear in Roman characters. You can sometimes use a foreign language address on the label if the names of the city, province, and country are in English.
However, character sets like Japanese, Chinese, and Cyrillic are often not supported by the carrier's label API, resulting in ??? symbols on the label where the characters should be.
In such cases, the best option is to translate the address into English (by either requesting it from your customer or using a program like Google Translate) and then edit the address in ShipStation to the English translation.
If you'd like to include the original address on the parcel, copy the original address to a program like Notepad, print it separately and tape it to the package next to the translated shipping label printed by ShipStation. This way you can ensure the address is legible in both the origin and destination countries.