I am travelling to Israel with my iphone 6 and iPad. I will rent a local cell phone, but do I need anything to use wifi and to plug in and recharge my devices? Do I need a power adapter of some kind?

Who is your current carrier?

What country are you coming from?

Why not rent just a SIM card to put in your phone?

Wifi is wifi, it is a standard and is not any different overseas.

If you're coming from the USA/non EU country see the note about the plug and adapters accordingly. Apple adapters are rated for 110/220v power, so you need just the pin adapters.

http://fpeb.blogspot.com/2009/06/electricity-in-israel.html