GST ON GTA under RCM and FCM

kindly explain few point of RCM and FCM inrespect of GTA

1. an unregistered GTA can charge gst from registered and unregistered service recipient under RCM OR only from registered service recipient....what will be the GST compliance for GTA ?

2. does a registered GTA under FCM liable to charge GST from registered as well as unregistered service recipient OR only from unregistered service recipient ?

3. when gta charge gst @ 12% ...will he be liable to claim ITC ?