who many different types of SIMs are available?

There are a few different types of SIM cards. They all do the same job, they're just different sizes
(like keys).
Your phone's designed to take one particular sized SIM, so make sure you've got the right one
for your phone or tablet. Here's some examples...
Full size SIM:
Apple iPhone 3GS
All USB modems
All Pocket WiFi modems
Samsung Galaxy Note
Samsung Galaxy SII
More.
micro-SIM:
Apple iPhone 4/4S
Apple iPad Retina Display
HTC One, One X, One SV, 8X
Nokia N9, Lumia 720/820
Samsung Galaxy Express, SIII, S4, Galaxy Note II
Sony Xperia S, TX, Z
More...
nano-SIM:
pple iPhone 5, 5c, 5s and iPad Mini
More...