hello everyone
I am new in Lora and I want to know that is it possible to have three Lora nodes in such a way that the first node send data to second and second to third and third send its info and and first and second node’s info to gateway?
If you search the forum, you will see this often comes up - under description of a ‘LoRaWAN Relay’ or ‘LoRaWAN repeater’, some ideas have been postulated around this - including some proposals from the original ‘inventor’ of LoRa at Semtech a couple of years ago, however, as yet there are no viable solutions in the market - the biggest issue is one of timing for any uplink and downlink (e.g. join req/ack etc.) The other is ensuring that any given downlink is correctly addressed to the end or itermediate nodes, etc.The LoRa Alliance continues to look at how this might reliably be achieved and develops draft proposals and requests for comment etc.
I would not hold your breath on this for now! 
In some non-LoRaWan schemes, yes, albeit with a fair amount of difficulty.
But not really within LoRaWan, which is all that is on topic on this particular site.
The closest would be the idea of LoRaWan repeaters, which are at the white paper / experiment stage - you can research those if you like but they are not presently supported by TTN or most LoRaWan nodes.
As @cslorabox says this is an option in LoRa only systems - I had clients doing LoRa repeaters 5-7 years ago in proprietary, non LoRaWAN environments, but these simply do not scale.
Dead easy, very simple code, but not a subject for discussion on the TTN forums. And whilst the code is simple it can go badly wrong which is another reason its not discussed on here.
Try the Arduino or Semtech forums.
what about hybrid mode I mean p2p/LORAWAN hybrid
Is it possible to use TTN?
You can do anything you like to get the data to a device that can then send a LoRaWAN packet.
But generally this hasn’t been found to be hugely reliable. So much easier to put a gateway on LTE in the midst of the devices.