Narrated Anas bin Malik: The Messenger of Allah ﷺ wanted to write to some persian rulers. He was told that they would not read a letter without a seal in the form of a silver ring on which he engraved "Muhammad the Messenger of Allah".
The Prophet Muhammad's use of his own name as a seal also serves as an example for us today; it shows us how we should strive to represent ourselves in all aspects of life, including our communication with others. We should always strive to be honest and respectful when interacting with people from different cultures or backgrounds, so that our words are taken seriously and respected by those who receive them.