The most basic features come with the LS trim level. It is the standard package. The LS trim level is very nice, but you do not get all the extra bells and whistles. It is also the least expensive. LT has all the same features of the LS or upgrades of the LS plus additional features. For example, a LS most likely has cloth seats where as a LT may have leather seats. Upgrades in the trim package can be both interior and exterior, such as more technology on the inside and painted-aluminum wheels on the outside. LTZ has all the LT features plus additional ones. Some of the extra features might be lower body side chrome moldings, heated front seats, rear view mirror camera and push button start. LTZ is the high end trim level and the most expensive.
If you visit www.chevrolet.com, you can compare models side by side to see which features come with each. Also, the comparison will let you know if there is a feature that isn't standard for that trim level, but is available for you to add on.