Whats the difference between these body style ive been trying to find out what the differences are and nothing

 

You must not have tried very hard. Those aren't body styles, they're chassis codes.

EM1 - 99-00 Civic SI. VTEC B16A2
EJ6 - 96-00 Civic DX/CX. Non-VTEC D16Y7
EJ7 - 96-00 Civic HX. VTEC-E D16Y5
EJ8 - 96-00 Civic EX. VTEC D16Y8