What are the head types of screws? What is the difference?

Screw is a general term for a fastener, a threaded fastener with various structural shapes. Screws include screws, bolts, studs, etc.
According to the type of screw head, it can be divided into several common head types: pan head, round head, cylindrical head, countersunk head, flat head, semi-countersunk head, semi-round head, hexagonal head, spherical cylindrical head, etc.
Different kinds of screws have their corresponding standards, and there are many types of slot types for screws, such as I-slot, cross slot, hexagonal, etc. Rarely, we see H-shaped, triangular, Y-shaped slot types, etc.