Can you give me any sample code to send at commands to outside module and receive return value?

[Yusuke]

I'm new to nRF9160. I have some experience of implementing stm32 MCU and HL8548(3G module). 

I want to send at commands to outside module like Wifi module, and receive return value from it.

[Hakon]

What do you mean by outside module? Is the wifi module on the same PCB as the nrf9160?