Mushrooms are like people: some of them are great to invite home to dinner, while others are poisonous and want to kill you. Do not rely on an app, or a downloadable fact sheet, or someone who says "yeah, these are probably fine."
Death caps, which look like edible field mushrooms when they're young. Do not eat. Photo by Hoarybat.
This is probably the most potentially deadly app I've ever seen pic.twitter.com/IrjuLSC6fZ
— Grant Williamson (@ozjimbob) July 24, 2017
There are tons of mushroom identification apps, marketed with varying degrees of responsibility. The one above is in beta (even though it currently costs $US4.99 ($6)) and its developer told Motherboard that it's meant to be a field guide for educational purposes. When I searched the iTunes store, the top mushroom identification app was one that includes a disclaimer that you shouldn't rely on it to tell you what's edible. But at the other end of the spectrum is an Android app called Edible Fungi that says all you need is "a good identification guide and a dash of common sense" to decide what to eat.
People die and get sick from eating wild mushrooms all the damn time. This includes poisonings from mushrooms that passed through the hands of foragers and chefs who should have known what they were doing, but still misidentified their mushrooms. If you'd like to start learning about mushrooms, it's better to find a club of local experts and learn about all the clues you'll need to identify a mushroom (like the colour of its spore print) that an app can't possibly evaluate. A dash of common sense is not going to cut it.
In short, if you need an app to identify edible mushrooms, you are not a person who has any business trying to identify edible mushrooms. Put that death cap down and go to the grocery store instead.