From heavy chunk to popping percussive single notes, the palm
mute should be part of your basic guitar technique vocabulary.
It is called a palm mute, but palm muffle is probably a more descriptive
name for this technique. Muting implies that you are not going
to hear the notes, but this is far from the case.
Here is the "chunk" technique. Especially when palm muting chords
with distortion, you will get a heavy percussive sound. It is
a staple in heavy metal, but this technique is used in all styles
Very lightly touch the side of your right hand at the edge of
the bridge. If you move your hand too far back behind the bridge,
you will not hear the muffled sound. If you move your hand too
far forward away from the bridge, you will completely mute the
strings and hear a click. I call this a "Palm Kill".
Watch this video of me moving my right hand to the left and right
while palm muting. You will hear the point when the sound is more
of a click, and the point where there is no mute at all.