Tap

or

in the top right of Feed.
- Tap
in the top right. - Select people you'd like to send a message to, then tap Chat.
- Type a message. You can also tap
to take and send a disappearing photo or video, or
to select a photo or video from your library. - Tap Send.
To message someone you follow, you can also go to their profile and tap Message.
Links you send will appear in the conversation with a preview image. When you send an address or phone number, you can tap it from within the conversation to open your phone’s maps app or make a call.
Keep in mind, Instagram accounts you message may use third party apps or automated services to send messages in chats.