The phrase "she possesses" is correct and usable in written English. You can use it when referring to someone owning something, either literally or figuratively. For example, "She possesses an impressive knowledge of 20th century literature.". She possesses it". She possesses herself.

"Posess" is an incorrect spelling, while "Possess" is correct and means to have or own something. How to spell Possess? You want to fully possess something, so make sure to use both 's's. Possession is something strong; it needs the strength of two 's's.

past tense of possess is possessed. He/She/It possesses . I possess. You/We/They possess. He/She/It is possessing. I am possessing. You/We/They are possessing. He/She/It has possessed. I have possessed. You/We/They have possessed. He/She/It has been possessing. I have been possessing.