E/F is F, E, G# and B. The shape this page opens on is written 122100, lowest string first.
Note by note. F is the root, E is the major seventh, G# is the minor third and B is the flat fifth.

Also written E over F or E with F in the bass. The same chord either way; which spelling you meet depends on who wrote the chart.
There are 6 common shapes for E/F on the guitar.
One note away. Change a single note of E/F and you have E (with one note taken away), Emaj7 (with one note moved), Eadd9 (with one note moved), E6 (with one note moved), E7 (with one note moved) or E7b9 (with one note added).
The common shapes, written lowest string first: 122100, xx3100, xx3454, xx7997, 8-11-9-9-9-x, x-x-12-13-12-12.
Under the hand. 2 of the 6 shapes here sit in open position, and the first uses 2 open strings. 2 of the 6 need a barre. Together they cover the neck from the 1st fret to the 13th.
What kind of chord this is. E/F is a slash chord — a triad over a named bass note. slash chords on every root, and what they are for.
The common shapes and the derived voicings come from different places, and both are explained in where the chords and the theory come from.
Shows each chord the way this style would voice it, and marks which of its alternatives belong to the idiom.