What Will Prince Charles Be Called When He Is King? It Depends

In an interesting British tradition, when he ascended to the throne, Charles could have selected any of his four names — Charles Philip Arthur George — as his formal king name, per the BBC. He is no longer known as the Prince of Wales, either, a title that may be bestowed to Prince William, who is now heir to the throne.

Source: https://www.distractify.com/p/what-will-prince-charles-be-called-when-he-is-king