Where can I purchase THETA fuel?

Excuse me, I'm curious about purchasing THETA fuel and am having a bit of trouble navigating the options. Could you please elaborate on the various avenues where one might acquire THETA fuel? I've heard about exchanges but am not sure which ones specifically offer this cryptocurrency. Additionally, are there any specific requirements or steps I should be aware of before making a purchase? I'd greatly appreciate your insight as a professional in the cryptocurrency and finance field. Thank you for your time.