When you are connected to a device programmed with firmware compatible with AT commands, for example AT Client sample from the nRF Connect SDK, you can switch to the Terminal tab to observe the AT communication with the modem and to send AT commands.
The terminal displays the AT communication with the modem.
To interact with the modem by sending AT commands, enter text in the command line located directly above the terminal and send it to the modem by pressing Enter or clicking Send. In the Line mode, the selected line ending is automatically appended to the command.
Each command is sent separately to the device, and the device processes each command and returns a response before waiting for the next command. This is the standard behavior for AT command communication.