These two terms are often misused by many people because they do not know the difference, and they think both have the same meaning. These terms are mostly used in spiritual and religious concepts. Incarnation refers to a living being embodying a deity or spirit. This concept is common among spiritual folks, and it is often attributed to spiritual beings that descended into a human form.
For example, Christians believe that the spirit of God incarnated into a physical human form, which is Jesus Christ. Reincarnation, on the other hand, refers to the rebirth of a soul in a physical form.
For instance, it is popular believes that the body is a shell for the soul. The body can be destroyed, but the soul cannot be destroyed. The soul will continue to reincarnate in order of physical beings.