One address, read by a person.
[email protected] reaches the person who builds the site. There is no ticket system and no chatbot in front of it.
The three things that make a bug fixable are which tool, which browser, and what you were doing when it went wrong. If a file was involved, its type and rough size matters — please do not attach it, since the whole point of the site is that your files stay with you.
If a tool produced the wrong answer rather than an error, say what you expected and what you got. That is usually enough to reproduce it.
Requests for tools that do not exist yet are genuinely useful, especially with a sentence about what you are actually trying to do — the underlying task is often served better by something slightly different.
The site is published in thirteen languages. If something reads awkwardly in yours, or a term is not what people in your country would search for, that is worth an email; corrections from people who speak the language are worth more than any amount of checking from outside it.
Copyright, privacy and other formal enquiries go to the same address and are answered by the same person. Please put the subject in the subject line so it is not missed among the bug reports.