Convert To Shia

Shia Islam is one of the two major sects of Islam and approximately 15 to 20% of Muslims are Shia. The split between Sunnis and Shias occurred following the Prophet Muhammad’s death. Sunnis believe holy Prophet, Muhammad (SAWA) chose no one to succeed him and Muslims themselves should choose their leaders after him, whereas Shias believe the prophet chose Ali (AS) in the event of Ghadir in his last journey to Hajj. Moreover there are a lot of historical documents that show the Prophet (SAWA) in several events during his life, talked about the leadership of Ali (AS) after him. You can see these documents in the book of Allameh-Amini: Al-ghadir
Although there is a division within Islam, converting to Shia Islam involves almost the same process as Sunni Islam. Converting to Islam is easy than the conversion process for other religions. 

Three Steps to Become a Shia 

Step 1 

Recite the Shahadah and mean it in your heart. The Shahadah is the Islamic profession of faith:
“There is no god but Allah and Muhammad is his messenger and and Ali is the wali of God (Vicegerent of Muhammad)” 
It must be recited in Arabic form:
اَشهد آن لَا إِلٰهَ إِلَّا الله و اَنّ مُحَمَّداً رَسُولُ الله و اَنّ علیّاً ولیّ الله
ash'hado allā ʾilāha ʾillā-llāh, va anna muhammadan rasūlu-llāh, wa anna ʿalīyyan walīyyu-llāh
Reciting these, you accept three fundamental beliefs of Shia. You must also believe in two others: Faireness of Allah and Resurrection.
Now, you officially become a Shia.
Every belief follows with some rules. Shia has its own rules that you must learn and practice it in your life.

Step 2

Obtain a Quran, the Islamic holy book. Quran is the word of God spoken directly to the prophet  Muhammad (SAWA). Read passages of the Quran for a better understanding of Islam. 

Step3

Learn about 10 Ancillaries of the Faith and perform them: 
 In these topics you must follow the Fatwa's of a religion expert (Mujtahid or Grand Ayatollah) like Ayatollah Khamenei, Ayatollah Sistani or others.