Hello, im new here and got a (few) question.

What is Original SME and original OEM (these 2 i always hear when someone ask seller the quality of product)? Whats the difference between those 2? Hows the warranty.

Scenario: Lets say i bought samsung wireless fast charge. The seller said its original OEM set. It broke down and i decided to tear it apart and found no fan inside (arent samsung wireless fast charge supposed to have fan inside?) So, OEM is a copy of original?