Esther 8:10

8:10 Mordecai wrote in the name of King Ahasuerus and sealed it with the king’s signet ring. He then sent letters by couriers on horses, who rode royal horses that were very swift.

Esther 3:12

3:12 So the royal scribes were summoned in the first month, on the thirteenth day of the month. Everything Haman commanded was written to the king’s satraps and governors who were in every province and to the officials of every people, province by province according to its script and people by people according to its language. In the name of King Ahasuerus it was written and sealed with the king’s signet ring.