A noise-canceling microphone will minimize the ambient noise that the other person hears coming from your phone. Headsets with longer microphone booms will make your voice sound stronger, with less echo and less background noise, than headsets with short booms. Headsets with short microphone booms can be stored in a pocket or pocketbook, and are good for a quiet environment. Headsets with long mic booms make your voice seem louder, with less echo and background noise. The adapter plugs into the handset jack on your phone, and both the handset and headset then plug into the adapter.
Some adapters go next to the phone, and others go underneath.
Adapters are also called amplifiers and switchboxes. AND you'll have to raise the handset. This depends on the design of the phone, not the headset or the adapter. They don't need adapters, and you don't have to raise the handset to use the headset. We also have wireless adapters that let you walk away from the phone on your desk, while you talk.