If you cannot get the link to work this is fro the ESRI Documentation....
Sign your iOS app
All iOS apps need to be signed. Apps created for testing must be signed by a developer certificate that is tied to your Apple developer account and the device on which you do your testing. A production certificate is tied only to your Apple developer account.
Before running the Make tool found in the AppStudio gallery side panel, either cloud or local, ensure that you have provided the following in the iOS tab of Settings, found under the Platforms heading:
Bundle ID—Always use a reverse internet domain name, for example, com.companyname.applicationname. The package name is a unique identifier for the app and is the default name for the application process. Once you publish your app, you cannot change the package name. For additional details, see the bundle ID explanation in Prepare for app distribution.
Provisioning profile—Indicates the devices where you plan to run your app.
Certificate (.p12 file)—Certificate for either the App Store or in-house distribution. This file is created in Keychain Access. If you do not supply both this information and the bundle ID in AppStudio, installation files will not be generated. For more information, see What is app signing?
At the time of running the Make tool, you will be prompted to supply the certificate password.
To create the certificate file required for signing, the following steps need to be performed once per developer and require a Mac:
Download your developer certificate (for example, ios_developer.cer) from the iOS Dev Center.
Download your mobile provisioning profile (for example, ios_developer.mobileprovision) from the iOS Dev Center.
Use Finder to browse to Applications > Utilities > Keychain Access.
Import your certificate into Keychain Access.
In Keychain Access, from the Keychain list, choose login, and from the Category list, choose My Certificates. Choose the certificate named phone Developer: Your Name and export the certificate with the private key with a password (for example, john_doe_private_key.p12).
Your certificate file is created.
In AppStudio, browse to Settings > Platforms > iOS.
Set the provisioning profile path.
Set the distribution type for your app. For more information on the options, see the Xcode documentation on distribution methods.