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...