To use voice communication in-game head to the Communication Panel in your cockpit (top left).
You can request voice communications with users in your vicinity as well as on your friends list using the Contacts Tab (tab 2). You can also mute or close any current voice communication from here too.
If you receive any voice communication requests these can be answered via the Notifications Tab (tab 3).
When you enter a wing you will automatically be able to use voice communication, if you’d rather not be opted in automatically then the Settings Tab (tab 5) allows you to change this.
To see if you’re currently using voice communication you can check the far right side of the communication panel. If you see an icon that indicates audio levels then you currently have voice communication active.