Signature of King Charles III of the United Kingdom, which features his regnal name (Charles), followed by the letter R for Rex, Latin for "king".
https://twitter.com/ggcanada/status/1574856998302191630 (Archived on 28 September 2022 at this address: https://web.archive.org/web/20220928115703/https://twitter.com/ggcanada/status/1574856998302191630)

File:Charles III Signature.png
Charles III of the United Kingdom