Can anyone tell me the difference between all these Volvos? I used to know when there was 242 and 244 and 245.

The 740 and 760, and 940 are older 4 cylinder turbo and non turbo rear wheel drive cars.
The 960 is a 6 clyinder rear wheel drive.
The 850 is a front wheel drive turbo or non turbo car.

Is there any difference in body styles in the 740, 940 and 850???

Yes they are different.The 740 and the 940 look very similiar.