After you have registered your number with Signal, you can start communicating privately with other Signal users. 

Here's how to send a message:

• Android
• iOS
• Desktop

Android

1. In Signal, tap compose  to view your Signal contact list.
2. Select a contact or enter a number to open that conversation.
3. Tap the text input field.
• You will see Signal message when you are securely communicating with another Signal user. 
  
• You will see Unsecured SMS when you are sending insecure messages through your mobile plan. Note: Signal is removing SMS/MMS support from Android. Read more on the blog post here.
  
4. Type your message or attach a file.
5. The send icon also indicates the message type.
• To send a Signal message, tap the blue send icon with a closed lock.
  
• To send an insecure SMS/MMS through your mobile plan, tap and hold or long-press the send icon to switch to the gray-icon. Note: Signal is removing SMS/MMS support from Android. Read more on the blog post here.
   

Having issues messaging on an Android phone? Follow these troubleshooting steps.

iOS

1. In Signal, tap compose  to view your Signal contact list.
2. Select a contact or enter a number to open that conversation.
3. Tap New Message to type a message or  to select a file.
   
4. Tap  to send. 

 Having issues messaging from an iPhone? Follow these troubleshooting steps.

Desktop

1. In Signal, select compose  to view your Signal contact list.
2. Enter your group name, contact name, or the full phone number.
3. Select the conversation or choose Start new conversation... after manually entering a phone number. It will appear on the right side of your contact list.
4. Select Send a message to type a message or  to select a file
   
5. To send, press Enter.

Having issues messaging from Desktop? Follow these troubleshooting steps.