There are no regulations, you can choose any name you want...
However, due to the influence of the geo-cultural factors of European city-states when football clubs emerged in Europe...most clubs will have the same name. The local place name + club name is used as the full name of the club. The clubs that emerged later generally followed this rule.
Football Club (or its synonyms or translations in each language) that can be directly added with a prefix or suffix to the place name is usually a very large local club, or the merger of several local clubs in a certain period Later, big clubs were formed, such as: Liverpool Football Club, Futbol Club Barcelona, ??Associazione Calcio Milan. However, after the merger, some are not called FC directly, but write United to indicate that we are the team after the merger, such as Newcastle United Football Club, Manchester United Football Club.
So, in addition to teams named purely after place names, other teams are actually called the latter part in the UK. For example, we call AC Milan and Inter Milan, but in fact they should be called Milan in Europe. and International...
As for China and South Korea... In fact, the club names behind are basically the names of the team owner's company or the main sponsor. Especially China. And because the names of Chinese teams have changed over time (the names have to be changed due to the change of owners), when foreign countries call Chinese clubs, they usually call them by their place names instead of their club names. For example, when it comes to Guoan, people just call it Beijing... But when it comes to Beijing Institute of Technology, foreigners can only call it Beijing XX University by its full name.
Japanese clubs are different in Asia. Except for corporate affiliated team leagues and school leagues, the basic club names of their teams rarely include the name of the sponsor. Most of the names are local characteristics, scenic spots, specialties and the like...such as Kashima antlers and so on...
Many places in Europe still have their monarchs, and the kings like to name people everywhere as a compliment. (Similar to the surname given by ancient Chinese emperors), and sometimes members of the royal family also like to own a team. At this time, teams that were awarded the title of royal family and were owned by the royal family had to add "royal" in front of the team name. This kind of situation is not common in the UK (QPR carries Queen, but it is because of the place name Queen Park, rather than really having any connection with the Queen), but it is almost everywhere in Spain... For example, Real Madrid, due to its success in the last century Achievements in the early and mid-term are praised by the king, and the word "royal" can be added.