Sending a direct message, or DM, on Twitter lets you communicate privately with other users. On the Twitter website, there is a dedicated Messages tab through which you send and receive direct messages.
Sign in to your account on the Twitter website and click the Messages tab along the top of the screen.
Click the New Message button to create a new message thread.
Enter the name or Twitter handle of the person to whom you want to send a direct message and then click the person's name on the list of search results. Repeat this step for each person you want to include in your new direct message thread.
Click the Next button when you've finished adding recipients to your direct message.
Enter your message in the provided field and then click the Send Message button to initiate the direct message conversation with your chosen recipients.
To send a direct message from the official Twitter app for mobile devices, touch the "Envelope" icon and then tap the "New Message" icon. Enter the names or Twitter handles of the people to whom you want to send a direct message, enter the message in the provided field and then tap the "Send" button.
If you don’t have the official Twitter app on your mobile device, use the mobile Web version of Twitter (see Resources). Touch the "Me" tab, tap "Direct Messages" and then touch the "Compose Message" button. Enter your desired recipients, input your message and tap "Send."
Twitter lets you send direct message only to people you are following. Similarly, you can receive direct messages only from Twitter users who follow you.