Although manufacturers have their own features and design and function can change, most hedge trimmers have a great many common features and the shape is relatively generic.
Here is a guide to the main features you will find on most double-sided models.
There are various adaptations of these basic features. For example the rear handle sometimes revolves to make angled cutting even easier and electric models will have cables and sometimes cable tidies.
Here is a similar guide for single-sided models
Single side trimmers are used with a single, sweeping motion and are used by professionals. They can be fitted with a leaf catcher, or guard, that attaches to the side of the blade and stops clippings falling back into the hedge (see image below)