Sending private messages to user

To send a message to a user you first need to obtain a User instance.

Obtaining a User instance

• use the message.author property of a message the user sent .
• call client.users.fetch with the user's id

Once you got a user instance you can send the message with .send

Examples

client.on('message', (msg) => {
 if (!msg.author.bot) msg.author.send('ok ' + msg.author.id);
});

client.users.fetch('487904509670337509', false).then((user) => {
 user.send('hello world');
});

The above answers work fine too, but I've found you can usually just use message.author.send("blah blah") instead of message.author.sendMessage("blah blah").

-EDIT- : This is because the sendMessage command is outdated as of v12 in Discord Js

.send tends to work better for me in general than .sendMessage, which sometimes runs into problems. Hope that helps a teeny bit!

In order for a bot to send a message, you need <client>.send() , the client is where the bot will send a message to(A channel, everywhere in the server, or a PM). Since you want the bot to PM a certain user, you can use message.author as your client. (you can replace author as mentioned user in a message or something, etc)

Hence, the answer is: message.author.send("Your message here.")

I recommend looking up the Discord.js documentation about a certain object's properties whenever you get stuck, you might find a particular function that may serve as your solution.