Direct messages are private between you and one other person (or a small group). You control how reachable you are.
Under User Settings → Privacy & Safety, you can allow or deny DMs from server members — globally or per server. On The English Hub you may allow DMs from people you met in voice, or restrict to friends only if strangers message you too often.
Friend request settings let you limit who can add you — everyone, friends of friends, server members, and so on. Declining or ignoring a request is normal; the other person is not notified harshly.
Never click suspicious links in DMs: fake Nitro gifts, impersonated staff, and crypto scams are common. Block and report to Discord when appropriate. If someone joined from our server and broke our rules, report-help with evidence is the right channel for server staff.
You are never required to reply to strangers. DMs with study partners you met in voice are fine; pressure to respond is not.