Starting at F, these are Major, Minor and 7th Barre Chords. Use your Index (1) finger to form the "bar." Once you learn these chords, you can slide the entire fixed fingering pattern up the neck to form a new chord on each fret. This means that once you learn this barre chord, you have actually learned 12 chords!
For example, the lowest Major barre chord based on E is F Major. Slide that fixed pattern up the next fret and you have an F# Major (See: Sharps and Flats). Slide up another fret and you get a G Major chord. All six strings can be played using this barre chord.
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