I am trying to simulate the circuit below. I am new to this software. How can I represent the toroidal coil named F and P in OrCad Pspice software?
Use two inductors with appropriate inductances (proportional to the number of turns squared). Define a coupling factor between them (an ideal tapped inductor would have K = 1). If you know the leakage inductance you can calculate the non-ideal coupling factor (K < 1). You can also include the winding resistance and even some parasitic capacitance.
The appropriate part is TFRM_LINEAR in the analog library.
However that simple model won't likely work for you in this particular case- this circuit depends on the transformer saturating so you'd have to find a nonlinear model including core saturation to get the oscillator to simulate.
A toroidal coil is just an inductor with a core shaped like a donut (toroid), but it's still a coil and has the same properties as a non-toroidal coil.
So in Pspice you can use the standard inductor to represent a coil. However what you have is more like an inductor with an extra connection halfway the inductor (sometimes called a centertap). This can also be seen as two inductors that are magnetically coupled.
You can model this in Pspice by using two inductors and defining a coupling factor between the two. If you know how many windings each inductor has you should be able to calculate the coupling factor from that.