Here, ‘recipient’ is the person you are sending a message to:
recipient.send("This is sent to your dm!").then(m => {
m.delete(10000) //Deletes the message after 10000 milliseconds (10 seconds)
}
Next time, try and do a little research first. You can also read the docs for discord.js which likely do have this issue.
solved How to make a Discord bot delete its own message from a DM? (Discord.js)