Barre chord
fret 4, E shape464544
A♭7 is the A♭ dominant 7 chord. Its notes are A♭, C, E♭ and G♭. It is the same chord as G♯7. A major triad with a flat seventh. Try G7 resolving to C.
464544
x-11-13-11-13-11
Numbers show frets from the low E string to the high e string; x means don't play that string.
A♭7 is the V7 chord in D♭ major. That makes it a natural fit in songs written in those keys.
Every A♭, C, E♭ and G♭ on the first 12 frets. The filled dots are the root, A♭. Build your own shape from any nearby group.
Other A♭ chords
Other dominant 7 chords