Every fingering that fits a hand
x666
moderate · barre · no 5
babx
easy · no 5
bab9
hard · no 5
What is true of it
G♭6 is G♭, B♭, D♭ and E♭ — 1, 3, 5 and 6 counted from G♭.
These are also the notes of E♭m7/G♭ and D♯m7/G♭. Which name is right depends on what is underneath and what came before — the notes alone do not decide.
On an instrument that cannot reach all 4, the 5 goes first, in that order.
The easiest of the 3 fingerings below is x666: one finger, one of them barring the 6th fret, held at the 6th fret.
None of them uses an open string, so this chord moves up the neck unchanged — the same shape 1 fret higher is the chord a semitone above.
1 of the 3 need a barre.
It leaves out the 5. 4 strings cannot carry 4 notes, and the 5 is the one this chord can lose without changing what it is.
1 string stays silent.
Where its notes are on the neck
The brass dots are G♭, the root. Everything else is a chord tone with its degree printed in it.
With a different note underneath
G♭6/B♭
3324
G♭6/D♭
6666
G♭6/E♭
x321
An inversion is the same chord with a different note lowest. The name changes to a slash name because the bass is what a listener hears as the foundation.