p.s. if you're not able to follow @Peru Bob's links to cancel your own account, using a browser that allows popups and cookies, contact adobe support by clicking here, https://helpx.adobe.com/contact.html?rghtup=autoOpen in the chat field (lower right), type AGENT be patient, it can take quite a while to reach a human
p.s. if you're contacted by anyone (via email or private message), it's much more likely to be a scammer than an adobe representative. ie, double check for an employee badge if contacted in the forums and look for an adobe.com domain in the email address if you click reply to an email. then check again and be very suspicious. any other method of contacting (or offering to contact you) is almost certainly a scam.
p.s.s. if you're cancelling an annual subscription beyond the trail period and before the end of your year, there's a penalty (=1/2 the cost of the remaining year).