Form 3115 needed? Can I file electronically?

I'm an individual l taxpayer.  I've used the accrual method for years to report interest on I bonds.  I now want to change to the cash method.  As I understand it, I don't have to file Form 3115, I can attach a statement which includes a number of things including a promise to report all interest going forward or when cashed.

 

Can I file electronically using desktop Desktop Deluxe TT if I attach a statement?  If so, how do I attach a statement?  If not, can I file electronically using Form 3115?

 

Thanks.