bet365 is legal in many European countries (including the UK, Germany, etc), the US (only in New Jersey, Colorado, Ohio, Virginia, Kentucky, and Iowa), Canada, a lot of Asian countries (Japan, Thailand, Singapore, etc.), and Brazil. Select a server in your home country and connect.
In general, there are not many countries that ban Bet365. In Europe, Bet365 is restricted to Turkey, France, Belgium, Netherlands, Portugal, Poland, and Romania. In Asia and Oceania, only the Philippines has banned this bookmaker. The most notable country that has banned Bet365 is the USA.