Add AllowAudioInput=True to the .ICAClient/wfclient.ini file in your home directory.
[WFClient] ... ... AllowAudioInput=True
NOTE: Ensure that this AllowAudioInput=True is placed within the [WFClient] section.
Disconnect and then reconnect to an ICA Session.
In Windows:
In Skype for Businesss, notice that both Speaker and Microphone refer to Citrix HDX Audio.
NOTE: Test that the Audio and Microphone are both working by clicking on the Check Call Quality button.
Remember also to configure your device's audio and recording settings appropriately.