When you start learning about music theory, you will come across the topic of chords and in order to have a strong understanding of music and how it works, you definitely need to know about chords.
Today we will be discussing piano chords.
In a nutshell, any two notes stacked on top of each horizontally can be classified as chords. However normally people associate chords with 3 notes or more.
The most common types of chords are major chords, minor chords, diminished chords and augmented chords.
There are many more types of chords including sus chords, minor sevenths, major sevenths etc.
The below infographic shows you the most common types of chords:
Daryl Green 
Andrew Williams 
Conrad Armer