a valid logbook is an official document and has to fulfill certain requirements, such as non-changeable, unique trackable etc - short, there is no electronic version for it for private flights yet
There's nothing in EASA regulations or CAP804 that specify this. The CAA will accept electronic printouts. A log book can be written on anything you want, and you are free to use Tippex.
I'm a big fan of
Logbook.aero. It's great for adding GPS logs and photos to flights.