There are some websites that teach people how to utter the Two Testimonies of Faith and become a Muslim through the internet. Is this permissible? If a person does so, will he be considered as a Muslim? Some people say that this is not permissible if this is done by writing and the person is not considered a Muslim, as this is like reporting and not believing in it [Declaration of Faith]. What do you think?

All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.

Uttering the Two Testimonies of Faith is a precondition for becoming a Muslim, unless the person is unable to do so, like being mute, for example. This is supported by several narrations. When the Messenger of Allaah, sallallaahu ‘alayhi wa sallam, sent Mu‘aath Ibn Jabal on a mission to Yemen, he told him the first thing to ask its people is to utter the Two Testimonies of Faith.  [Al-Bukhari, An-Nasaa’I and Ad-Daarimi]

An-Nawawi from the Shaafi‘i school, said that the scholars of Ahlus-Sunnah all agree that a person is considered a Muslim and will not be eternally in Hellfire, if he firmly and sincerely believes in Islam without having any doubts about it, and utters the Two Testimonies of Faith. If he only does one of the two, he would not be considered a Muslim and he will be in Hellfire forever unless he is unable to utter the Two Testimonies of Faith because he has a problem with his tongue or because he is dying, in which case he can be considered a Muslim.

Therefore, the people who invite the non-Muslims to Islam through the internet should ask them along with writing the Two Testimonies of Faith to utter them.  

Allaah Knows best.