Fretting is pressing the strings down against the frets to shorten or lengthen the string to create higher or lower tones. Fretting also includes slurs (using the fretting hand to alter string tones). The fretting hand can pluck and strum just like the motor hand.
Muting/touching (mute/touch) is using the fretting hand to block the strings without pressing. We have some strumming with mutes in the strumming section (what we call pre-chord sounds). These are also listed in Chords.
The fretting hand is integral to creating sweet tone and rhythm. Experiment with fretting hand nail length, as this will affect tone and slurs (cutting them all the way down is not the best option).
Open & Closed • Fretting Confidence • These are the two basic states of a string. We know that tones are going to work.
Slurs • Slurs are fretting hand articulations. They connect tones. They are a way to create legato between tones [connected & smooth]. There are 5 types: pulls, hammers, slides, bends, and vibrato. They are used extensively in soloing and chord playing. The Pull has its own page in Scales & Modes.
Barring • Barring is fretting more than one string, in the same fret space, with the same finger. Multiple fingers can bar at the same time. Think of an A chord (x0222x): it can be barred with the 1, 2, 3, or 4 finger (though the 3 and 4 aren't common at the 2 fret for the A chord, either can be used for the bar in the A form once it moves up the board).