Types of glass

Flatconvex and wide-angle.

The flat mirror gives a 1:1 vision. The radius of curvature (ROC) of spherical convex mirrors is 1200 and for wide-angle/blind spot mirrors ROC is up to 340.

What is this mean?

Flat vision is the same as a typical bathroom mirror. 
Convex and wide-angle mirrors give smaller vision and thus allow to see more objects in the reflection. Now car manufacturers use only convex mirrors for door wing mirrors as standard. You can find flat mirrors in old cars. The exception is the US and Australia where you can still find flat mirrors on the passenger side.

In most the cars convex/spherical mirrors are used on the passenger side and wide-angle mirror with a blind-spot section on the driver side.