The D sharp dominant seventh chord is a 4-note chord consisting of the notes D#, F##, A# and C#.
You can see these notes highlighted in the interactive piano chart below.
The chord itself is often abbreviated as D#7.
Chords that are a superset of D#7. The chords include more notes but always D#, F##, A# and C#.
Chords that are a subset of D#7. These contain less notes but all of them are included in D#7.
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 D#7 chord. Feel free to save or share the image as needed.