The G suspended fourth chord is a 3-note chord consisting of the notes G, C and D.
You can see these notes highlighted in the interactive piano chart below.
The chord itself is often abbreviated as Gsus4.
Chords that are a superset of Gsus4. The chords include more notes but always G, C and D.
Chords that are a subset of Gsus4. These contain less notes but all of them are included in Gsus4.
In case you prefer a non-interactive variant of the chord chart, we've embedded a PNG image below that shows the notes for the the Gsus4 chord. Feel free to save or share the image as needed.