I understood that Webroot 2015 Security Complete could be installed on my iOS iphone without more$

Hello there, welcome to the Community!
 
I am not an expert on iOS, but it sounds like you downloaded the Business version. That DOES require an invite code.  I believe you should be using different downloads, as iOS device IS covered under your WSA-Complete license.
 
? are you still around?  Can you help guide us to the correct iOS downloads so that I do not miss anything?

Hello ?,
 
Welcome to the Webroot Community,
 
Yes you have downloaded the Webroot Business version.  Please delete that app. This requires a invitation code as noted.
 
Sorry WSAC does includes ithese mobile devices here such as Android/Smart Phones.
 
Please look at this information below,
 
At this time, there is not an antivirus option available for Apple iOS devices. Because of how Apple manages the apps available in their App Store, there is not a need for one currently. This may change in the future but at this time is is extremly hard/almost impossible to infect an iPad and iPhone.

 
Webroot does offer two apps you can download from the App Store to backup your files and protect your internet browsing, called SecureWeb and Backup & Sync. You can find either of them by searching for "Webroot" in the App Store on your Apple iOS device. For more information on both of these products please use the information below.
Webroot SecureWeb
https://mobile.webroot.com/brands/webroot/en/help/ios/SecureWeb/index.htm
Webroot Backup & Sync (for SecureAnywhere Complete subscriptions only)
https://mobile.webroot.com/brands/webroot/en/help/ios/SecureSync/index.htm
 
But here is more in depth information for WSA Complete for IOS,
First, let's make sure you're following these instructions for installing Webroot SecureAnywhere Complete on an iPhone
 
iOS Download Instructions 
To download the SecureWeb app:

1. If you have not yet created a Webroot account, go to https://my.webrootanywhere.com. Click Sign up now to begin creating the account.  
2. Open the Apple Store on your device and search for “Webroot SecureWeb.” & "Password Manager & Backup & Sync  to install these apps. Alternately, you can download and install the SecureWeb app from iTunes at: http://itunes.apple.com/us/app/webroot-secureweb-browser/id460986853?mt=8  
3. Enter your Apple ID password. The SecureWeb app opens and installs on your device. Once installed, you will see the Webroot SecureWeb icon on your Home panel. Tap this icon to open the app.  
4. To access Password Management functions, tap the key icon in the SecureWeb toolbar. Enter your SecureAnywhere user name and password. This is the same login that you use to access your Webroot account at my.webrootanywhere.com. If you have not yet created a Webroot account, go to my.webrootanywhere.com. Click Sign up now and complete your registration. When SecureWeb validates your Webroot credentials, a green checkmark appears above the key icon.  
5. For more information, see Webroot SecureWeb for iOS Help.

You will need to check your permmissions  to your account permissions, sign into http://my.webrootanywhere.com, click your email address at the top right of the console, click Manage Users, and click the little person with the pencil icon on the right side of the screen.  Ensure that all of the values for your user are set to either Access or Admin level and that there are checks in the Passwords and Passwords Service boxes.
 
 
Hope this helps,
 
 
Kind Regards,