What's the difference between 帐户 and 账户?
账户 is the correct form, and 帐户 is a common typo seen a lot in online services. 

账 or 账本 means "books", and 记账 is the action of "accounting". The word 账户 means a "bank account", and is also used as "online account" nowadays. 

帐 has meanings related to cloth, like "mosquito net"(蚊帐) or "tent"(帐篷). 

P.S. There is no entry for 帐户 in The Standard Dictionary of Contemporary Chinese.