The Sharingan is one of Kekkei  Genkai that naturally occurs in a select few members of the Uchiha clan.  When the user is in a life-threatening situation, Sharingan usually  appear to save them. Only few person that possess the Sharingan, some of  them are Sasuke Uchiha, Itachi Uchiha, Kakashi Hatake, Madara Uchiha  and Madara's brother. The power of the Sharingan is judged through the  number of tomoe in the eye, with a maximum of three in each.
Sharingan's Level
 The Sharingan's first level
The Sharingan's first level  and most well known ability is to memorize any technique that it  witnesses. The user pupil will turn red and develop one of the wheel  swirls. It can memorize any standard form of jutsu with perfect  accuracy, allowing the user to use the techniques as his own. Based on  Naruto storyline it was released when Sasuke for he first time fight  againt Rock Lee taijutsu. Sasuke make some copy of Lee's move and show  it when he fight Akado Yoroi, even he is able to modified with his own  move.
 The Sharingan's second level
The Sharingan's second level  ability is granting the user incredible clarity of perception, allowing  them to track fast-moving objects with ease and even predict the  subsequent movements of those objects. The user pupil will turn red and  develop two of the wheel swirls. This second levell was show up when  Sasuke took Chunin Exam. Sasuke was able to reproduce answers on another  person's test by watching their pencil movements and copying their  answer.
The Sharingan's third level  capability is a unique brand of hypnosis that involves suggesting  actions and thoughts to the opponent. The user pupil will turn red and  develop three of the wheel swirls in both eyes. In this level the user  can read Genjutsu, Taijutsu and Ninjutsu, learn how the skill is done  and then copy it to be used later. This allows the user to perfectly  mimic every move their opponent makes, even before they do, making it  appear as if the user can see the future.
The last level is 
Mangekyo Sharingan,  it is a heightened form of Sharingan. Madara Uchiha become the first  person which awakened Mangekyou Sharingan. Then his brother also  awakened Mangekyou Sharingan. With that power both of them be the  strogest person in their clan. Mangekyou Sharingan was able to use it to  gain control over the Nine-Tailed Demon Fox. After Madara and his  brother only three person could do the same thing, they are Itachi  Uchiha, Kakashi Hatake, and Sasuke Uchiha.
 Sasuke Uchiha's Mangekyou Sharingan
Sasuke Uchiha's Mangekyou Sharingan
Sasuke initially caught a glimpse of this version of Itachi's Mangekyou which differed from his later version.
 Itachi Uchiha's Mangekyou Sharingan
Itachi Uchiha's Mangekyou Sharingan
Itachi  was able to finally master this form during the period he killed his  clan. Itachi get this Mangekyou Sharingan after killed his closest  friend. In this form Itachi is able to use the Amaterasu and Tsukuyomi  Doujutsu techniques.
 Kakashi Hatake's Mangekyou Sharingan
Kakashi Hatake's Mangekyou Sharingan
Even  Kakashi isn't from Uchiha clan, Whether this form is due to Kakashi or  some inheritance from what Uchiha Obito was capable of is unknown. Using  the eye, Kakashi can use a technique which appears to collapse space in  around a focus point and transport it to another location.
 Madara Uchiha's Mangekyou Sharingan
Madara Uchiha's Mangekyou Sharingan
After  developing the Sharingan, Madara and his younger brother trained  against one another and eventually awakened their own version of the  Mangekyou. The use of these eyes increased the brothers' strength and  allowed them to take over leadership of the clan. Unfortunately the  usage of the eyes lead Madara to lose his vision.
 Madara's Brother's Mangekyou Sharingan
Madara's Brother's Mangekyou Sharingan
After  developing the Sharingan, both brothers trained against one another and  eventually awakened their own version of the Mangekyou. The use of  these eyes increased the brothers' strength and allowed them to take  over leadership of the clan. But because of Madara as the lead get  blindness, he give his eye into Madara.
 Madara Uchiha's Eternal Mangekyou Sharingan
Madara Uchiha's Eternal Mangekyou Sharingan
Those  who possess a Mangekyo Sharingan suffer from ever-deteriorating  eyesight, a process that becomes faster through repeated usage and  culminates in blindness. nly by taking the eyes of a sibling can one's  eyesight be permanently restored, combining the appearances of the two  Mangekyo Sharingan and granting them immense strength in the process. As  a result, Madara awakened a new more powerful set of eyes which allowed  him to see the light once again.