1. Select 
Groups
2. Select the group you would like to add a voice message in
3. Select the text field box that reads Share a Post with your Followers
4. Select the Mic icon 
to record your Voice Message
1. Tap 
Communities
2. Select the group you would like to add a voice message in
3. Select 
4. Tap the Mic icon to record your voice message
1. Tap Communities
2. Select the group you would like to add a voice message in
3. Select
4. Tap the Mic icon to record your voice message