The Ruling on Marriage by Correspondence or via the Telephone
Question :
Is marriage via the telephone or by correspondence daughter in marriage via the telephone or via a specific letter?
Answer:
A Marriage is not contracted via the telephone, nor by correspondence; rather, the husband and the (bride's) guardian must attend, along with the witnesses and this cannot be completed via the telephone or by correspondence. Yes, it might be completed through correspondence, if the contractor appoints a proxy to contract it for him if he is in another country. In these circumstances, it is required that the document appointing the proxy be an authorized document, as established by the Islamic Law.
Source:
Ibn 'Uthaimin
Fatawa Islamiyah, Vol. 5 Page 188