(iOS)
There are multiple ways to send a message, from your contact list, from a existing conversation, from the compose button.
Let's say you want to send "Miss you!"
1. If your friend is already in your contact list:
- Tap Contacts (1a)
- Find your friend among your contacts list
- Tap Message icon
- Choose the number you want to send your message from
(if you have multiple numbers) - Compose your message and tap Send (2a)
(1a) 
(2a) 
—
2. If your friend is not on your contact list:
- Tap Inbox (1b)
- Tap + icon (2b)
- Compose your friend number (you will have to switch the
keyboard into number by taping 123 key) - Compose your message and tap Send (3b)
(1b) 
(2b) 
(3b)
3. If you have an existing conversation with your friend:
- Tap the conversation
- Compose your message in the conversation field, tap Send
That's it! Let's wait for the answer!