Although you might find small Yu-Gi-Oh! Goat Format tournaments in some areas of the world, it is mostly played online. There are a number of Yu-Gi-Oh! dueling simulators that allow this to be possible. The one that we recommend using at this time is DuelingBook.com. It is flexible, user-friendly, and it even has its own room for Goat Format games.
In order to find people to play against online, we recommend joining our Discord server. Discord is a text-chat app (similar to Skype) that is widely used by the gaming community. On our Discord server you can not only find people to play games with, but also discuss strategy with others and get help with the format from more experienced players.