Karma has a threefold classification:

1. Mental karma- created by the mind and thoughts,
2. Verbal karma- created by the speech, and
3. Bodily Karma- caused by physical actions.

Mental karma is the most significant of the three because it gives rise to, and is the origin of the other two types of karma. We think before we speak or physically do someting, however brefly, and our thoughts influence wat we say and do.
Furthermore, two types of karmic actions are described here: ones that are postive, skillful, beneficial, and also good, and those that are negative, unskillful, harmful, and ultimately bad.