Well the answer to this question is fairly straightforward really, basically the LGV C and E test was originally known as HGV class 1, which allows drivers to be able to drive any rigid vehicle and a trailer over 750kg with a combined weight of 44 tonnes (truck and trailer). If you successfully pass the LGV C and E test you will be able to drive articulated lorries which are also known as artics and also trucks that have a drawbar trailer.
With your C and E license you will also be granted C1 and E entitlements automatically, this means you can drive a 7.5 tonne lorry plus a trailer. You will also be automatically granted a category B and E license which will entitle you to drive a car plus a trailer towing.
If you have a PCV license for instance at category D or D1 you also have entitlement to tow a trailer over 750kg, so as you can see passing your C and E test will enable you to drive a wide variety of vehicles with different weights and trailers. I wish you the best of luck with it all!