I wanted to simulate a Ground Fault Circuit Interrupter, namely RV4145. On other site someone asked the similar question ,

https://electronics.stackexchange.com/questions/402520/automatic-self-test-circuit-in-gfci-outlet
(Automatic Self-Test Circuit in GFCI outlet)


Here in the snapshot @ nickalexeev have provided a part of the schematic. Can someone please explain how it was done? Which simulation software was used?

 

Can someone please explain how it was done? Which simulation software was used?

Likely a Spice simulator such as Multisim, or PSpice.
Several here (including myself) use the free LTspice from Analog Devices, but that doesn't look like an LTspice schematic.

 

Here in the snapshot @ nickalexeev have provided a part of the schematic. Can someone please explain how it was done? Which simulation software was used?

Any spice based software can be used, and a spice model of the RV4145 made by the user, or obtained from the manufacturer.
The schematic you've posted is missing some components that help describe how it works. But basically, TI is a current sensing transformer that is the AC input interface to the RV4145. The RV4145 detects an unsafe level of AC current and opens (breaks) the AC supply circuit, disconnecting the AC load.