How to distribute iOS app to device or app store or testflight

Prepare Provisioning profile:

Keychain Access-->Certificate Assistant-->Request a Certificate from a Certificate Authority-->input email address (App ID), saved to disk.
Sign in https://developer.apple.com-->iOS Provisioning Portal-->Certificates-->Request Certificate-->input the certificate you saved to disk-->Submit. (Administrator will approve it.)
From the email you input in keychain access, click the invitation code, and you will be invited to "Apple Developer Program"

Download provisioning profile: Xcode-->Organizer-->Devices-->Library-->Provisioning Profiles

Click Referesh: input App ID, download many profiles, not only yours.
Sign in https://developer.apple.com-->download your profile to disk-->drag it to provisioning profiles-->just your profile list there.
You may have two profiles: one is a specific profile (i.e. it can be just used for specific app), the other is a generic profile. (i.e. it can be used for all apps you develop)

Xcode-->targets-->your app-->change "code signing identity" to your identity. Then you can select you device from scheme, to run/debug/install you app in your device.

Distribute:

Xcode-->Product-->Archive-->generate .xcarchive file to disk, and it is also listed in Organizer-->Archives
Organizer-->Archives-->click one .xcarchive you generated-->Distribute:

Submit to the iOS App store: distribute to app store.
Save for Enterprise or Ad-Hoc Deployment: distribute to other places outside of app store-->Code signing identity(your identity)-->save ipa(build file) file to disk. (not check enterprise distribute)

Distribute to iTunes:

Double click the ipa file and it will be store to iTunes.
Connect iOS device to mac.
Click the iOS device in iTunes.
Select Apps menu, and you will see your app that was stored in iTunes just now.
Click install button for you app or drag it to the screen of iOS device in the right part.
Click Apply button at the right-bottom corner to install your app to iOS device.

Distribute to testflight:

Sign in testflight web site (you need register in it first)-->Add a build-->upload the ipa file you saved to disk.
You can install/run you app in your device via testflight.