Siri personal assistant gets more useful with every iOS upgrade – she can probably do more things than you expect she can. She can be useful for everyone but especially useful for people whose disability makes manual use of their iPhone difficult, slow, or painful.
I especially recommend that new users start with How to set up, secure, and start using Siri which will walk you through initial one-off setup and configuration for Siri.
Siri has so many functions now that to list all of them is virtually impossible – iMore has done a pretty good job though, and frequently upgrade their articles as Siri’s functions are upgraded:
Once you see just the index on the iMore list – with its 61 different functions – you start to realise why it’s impossible to provide a Siri “cheat sheet” that will list every command the way we can do with Siri’s earlier cousin, Voice Control.
The Techblog Full List of Siri Commands is not a full list but is formatted so it’s a useful cheat-sheet type document and does seem to have most of the more commonly used commands in it.
Having trouble? Start with Apple’s Troubleshooting Siri page. If that doesn’t help, try googling as there are a lot of articles around the internet with useful information too. For those questions you can’t find answers to in the above articles, or via google, there are two user forums that seem active at present:
For those with severe disabilities, please note that Siri today with iOS 7 is not yet going to let you use your iPhone with only speech (“hands-free”) or even close to that. It can perform a fair number of functions but you will definitely still need to supplement speech with some other type of input – be it touch, switch input, mouth stick, or something else. Hopefully in future speech-only iPhone access is something that Apple will implement, the “Hey, Siri” hands-free iPhone activation promised in iOS 8 seems to be a useful step in that direction but it’s only one step and there will be many more steps needed.