The D flat major chord is a 3-note chord consisting of the notes Db, F and Ab.
You can see these notes highlighted in the interactive piano chart below.
The chord itself is often abbreviated as DbM.
Chords that are a superset of DbM. The chords include more notes but always Db, F and Ab.
Chords that are a subset of DbM. These contain less notes but all of them are included in DbM.
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 DbM chord. Feel free to save or share the image as needed.