What is the first chord I play in my singing?

Don’t forget that there is a D sound on the left hand. Chords refer to the combination of all notes at a certain time. You can't ignore the lowest note in your left hand and just ask what chord it is in your right hand.

Based on this, we can see that this chord is D-E-F sharp-A, which is a commonly used chord in popular piano music and is called the Dadd2 chord. add2 means adding the major second note above the root note. The D chord is D-F sharp-A, the root note is D, add a major second to the D chord, which is E, and you get the chord you asked about.

If it is based on Western classical harmony theory, the E is generally considered to be an outtone of the chord. However, since it is a popular piano piece, it should not be analyzed according to European classical harmony theory.

If you have any questions, please ask me!