To convert to Islam, a person must repeat the shahaadah, declaration of faith, in front of two witnesses. The shahaadah is as follows: I witness that there is no God but God, and that Muhammad is the Messenger of God.
Gulevich, Tanya. Understanding Islam and Muslim Traditions: An Introduction to the Religious Practices, Celebrations, Festivals, Observances, Beliefs, Folklore, Customs, and Calendar System of the World’s Muslim Communities, including an Overview of Islamic History and Geography. Detroit, MI: Omnigraphics, 2004.
To read Understanding Islam and Muslim Traditions, please see attached document.