Creation
Jafar is a Disney original character, created for Disney’s version of Aladdin, although does take inspiration from “The Second Genie” & “The Grand Vizier” from the original story written by unknown Middle Eastern and Middle Asian writers from 1706.
Major Story Arcs
Aladdin
Jafar was once the royal vizier of Agrabah and the Sultan‘s most trusted adviser. However, he harbored a wicked desire to reign over Agrabah himself, attempting to locate the Genie‘s lamp and use the wishes to put himself upon the throne. Though initially successful in his endeavors, Jafar was soon thwarted after his enemy, Aladdin, goaded him into wishing to become a genie. Because of the limitations inherent to genies, Jafar, along with his parrot Iago, was sealed in a lamp, ending his reign as quickly as it had started.
Aladdin: The Return of Jafar
In the sequel, Jafar’s lamp is found by the thief Abis Mal, setting the malevolent genie free. Immediately, Jafar sets into motion a plan to exact revenge upon Aladdin. However, at the hands of Aladdin, his loved ones, and the recently redeemed Iago, the lamp binding Jafar is destroyed in lava, thus vanquishing the evil genie once and for all.
Other Appearances

Jafar being a popular Disney villain was included in plenty of non-canon golden kid books and comics, as well as being the main villain of the Halloween special, Mickey’s House of Villains. Where he took over Mickey’s show and showed only sad endings or dark stories.
Other Versions
Once Upon A Time In Wonderland

Jafar was a main character in the spin-off series where he’s revealed to have been the unknown son of The Sultan (Ultimately making him Jasmine’s half brother.) He tried to kill Alice and the Wonderland characters, as well as having a past with Cyrus (the renamed Genie) Jafar was played by Naveen Andrews.
Once Upon A Time
In the same canon, Jafar would return for the sixth season of the series, although recasted with Oded Fehr. Jafar was based off the original Disney character more closely, trying to kill Aladdin and take over Agrabah. He was also shown to still wish to marry Jasmine, who in this canon is his half sister, although despite that being a plot point in the spin off series, is at no point mentioned in the main series, likely to avoid incest controversy.
Aladdin (2019)

Jafar was the main villain of the live action remake of Aladdin, playing the same role as the one from the original animated movie, with the only changes made to the character being his interest in Jasmine. Instead of one sided love, Jafar’s care for Jasmine is now only for desire to gain more power. Like in the original animated feature he would hire Aladdin to get the lamp only for Aladdin to use it for himself, leading to Jafar needing to find other ways to take over Agrabah. The movie would end with Jafar and the Genie swapping places. Jafar was played by Marwan Kenzari.