The non-Muslim becomes Muslim by believing in the two testifications of faith, and uttering them with the intention of leaving out blasphemy.
The two testifications of faith are: I bear witness that no one is God except Allah, I bear witness that Muhammad is the Messenger of Allah.
Which means I know, believe and declare that no one deserves to be worshipped except Allah, and I know, believe, and declare that Muhammad, the son
of Abdullah, who was bord in Makkah and died in El-Medina, is the Messenger of Allah, to all humans and Jinn.