Slotted
The original single slot. Bit cams out easily.
Two different questions, two different answers. The drive is the recess you put a bit into (Phillips, Torx, hex…). The head shape is the profile of the head itself (flat, pan, round…). Here's every common one, drawn to identify at a glance.
Match the bit to the recess. Using the wrong one (a Phillips in a Pozidriv, say) is the fastest way to strip a screw.
Countersunk heads (flat, oval) sink flush or below the surface; raised heads (pan, round, truss) sit on top. The grey line is the material surface.
Drive and head are independent — you'll find, say, a flat-head Phillips wood screw and a flat-head Torx deck screw. Spec both when you order: head shape + drive + size.
A Phillips is a plain cross. A Pozidriv adds a second, smaller set of lines at 45° between the cross arms (and usually tiny ticks stamped on the head). A Phillips bit fits a Pozidriv loosely and will cam out and strip it — and vice versa. Match them.
Torx is a 6-pointed star with curved lobes; a hex socket is a plain six-sided hexagon with straight walls. If a hex key spins freely, you're looking at Torx.
Its cone lets the head sink flush with — or below — the surface, so nothing protrudes. It needs a countersunk hole or a countersink bit to seat properly. Raised heads (pan, button) sit on top and don't.
No — they're two separate specs. The head is the outer shape (flat, pan, round). The drive is the recess a bit engages (Phillips, Torx, hex). Any head can pair with most drives.