Sanchita karma is the total accumulation of karma from your past lives.
As Karma became a daily used word in parts of the world, people often had a generic understanding of karma, let me repeat what it can be “Karma is translated as action or deed”
Prarabdha karma is the chunk of sanchita karma you are going to experience in your current life.
The end goal is no sanchita karma left and thus no re-birth.
The earliest reference to Karma happened in “Brihadaranyaka Upanishad“
Now as a man is like this or like that,
according to as he acts and according to as he behaves, so will he be;
a man of good acts will become good, a man of bad acts, bad;
he becomes pure by pure deeds, bad by bad deeds;
And here they say that a person consists of desires,
and as is his desire, so is his will;
and as is his will, so is his deed;
and whatever deed he does, that he will reap.
