Of the four characteristics, karma is the most well-known and the most misunderstood. Some karma can be changed and some cannot. Prarabdha means begun, the action that is already manifesting. Prarabdha is the karma that is yielding its fruits, its effect, right now. You cannot avoid it, or change it because it is already happening.
Sanchita karma is the “gathered up,” or “piled up,” karma. It is latent or in the form of a tendency. An impression in the mind is a latent action. It is still action, but it is latent. This is just like a memory. A memory can be functional now or latent. Sanchita karma can be burned off, changed, by spiritual practices before it becomes manifest.
Agami literally means “not come.” Agami karma is the karma that has not yet come, that will take effect in the future. If you commit a crime, you may not get caught today, but you will live with the possibility that one day you may get caught. This is agami karma, the future karma of the action.
Every habit is a sort of karma. If you have the habit of drinking coffee every morning, and one day when you don’t drink it and you get a headache, this could be called coffee karma. You can postpone the headache by drinking more coffee or you can take steps to eliminate future coffee karma and stop drinking it and observe what happens to you. Perhaps you will have headaches for some days, so you start some exercise program, or some meditation or breathing practices.