In this topic I will show you how to harmonize a melody.

If we have this simple melody:
C, D, E
Click to view attachment

We can harmonize this with one chord. A chord which contains the start point © and the stop point (E).
Start with chords from tonality of C .
So, this chord could be (in order from each step.
C or CM7 or C6 or CM9 or CM11 or CM13
Dm9 or Dm6,9
Em7(b9, b13)
FM7 or FM9 or FM9(#11)
G13
Am or Am7 or Am9 or Am 11
Bm11(b5,b9)

the following track begins with the melody without chord and then harmonize this melody using
CM7 - Dm9 - Em(b9) - FM7 - G13 - Am9 - Bm11(b5,b9) progression.

Click to view attachment

not necessarily to have all the notes in the chord. for example, if you have C, D, E in melody, and play Em7(b9) wich contains E, G, B, D, F, the melody with harmony create the full chord : E, G, B, D, F, A, C - Em7(b9,b13).

enjoy!