Question: I see that some organisations are offering people to sell their chametz online. Is this ideal?
Answer: The Shulchan Aruch (OC 448:3) writes that one may sell their chametz to a non-Jewish person for the duration of Pesach. R’ Shlomo Yosef Zevin (Hamoadim Behalacha, quoted by R’ Ribiat, Halachos of Pesach, p172) describes the history of selling chametz. While individuals used to sell their own chametz, they were fraught with complications and errors. Especially as most times the chametz never leaves the house, the forms of acquisition are most complicated (See Magen Avraham OC 448:4). As a result, communities began selling their chametz through their local rav and Beis Din.
The Aruch Hashulchan (OC 448:27) explains that nowadays the rav acts as an agent for anyone who has appointed him to sell their chametz.
While it is possible to appoint an agent verbally (Shulchan Aruch EH 141:26; CM 182:1), Rambam (Mechira 5:12) writes that it is customary to perform a kinyan (act of transaction) to solidify one’s appointment of an agent.
Nonetheless, it is important that the chametz gets sold properly and that all parties involved view it as a legal sale rather than a mere ritual. Thus, it is common practice to fill out a form that acts as a legal document (shtar) as well as to engage in a kinyan sudar, a symbolic act of transaction performed with a cloth which demonstrates the transfer of authority through this agent.
Thus, R’ Ephraim Greenblatt (Rivevos Ephraim 1:293) writes that while one can appoint their rav to sell their chametz over the phone, it isn’t ideal.In conclusion, one should try their utmost to sell their chametz in person with their rav, due to the severity of the sale. One who is housebound can sell their chametz online or by phone if necessary.