Q: Can I transfer my apps from my old iPhone to a new one through iCloud? If so how?
A: The short answer is yes, provided that your old iPhone supports iCloud, all of the apps that you wish to transfer are still available on the App Store, and you’re setting it up as a new iPhone.
To do this, you simply need to ensure that you have setup iCloud on your original iPhone with iCloud Backups enabled. You can find the option for this in the Settings app under iCloud, Storage & Backup.
From this screen you can also see the date and time of your last backup to the iCloud servers; iCloud backs up your iPhone once every 24 hours as long as it is connected to a Wi-Fi network and a power source. If you have not made a recent backup, you can do so manually as long as you’re on a Wi-Fi connection by tapping the “Back Up Now” button.
By default, your iCloud Backups include all of your settings and application data along with a list of the apps and media content stored on your device. You can confirm that everything is being backed up by tapping “Manage Storage” from the Storage & Backup screen and then tapping your iPhone in the list of devices; your total backup size will be shown here along with toggled to exclude certain items from being backed up. Note that unless you’ve changed these settings, everything will be backed up by default, but you may want to check here just to make sure.
Once you’ve confirmed that you have a recent backup of your existing iPhone in iCloud, you can proceed to setup your new iPhone, choosing to restore from your iCloud backup when prompted and then simply signing into iCloud and choosing the appropriate backup from the iCloud server (if you’re backing up more than one device to iCloud).
Restoring from iCloud works in much the same manner as restoring from iTunes. Your settings and data will be restored directly from the backup after which iOS will begin downloading and installing all of your apps and any of your media content that was purchased from the iTunes Store. As applications are reinstalled on your device they will appear greyed out on your home screen with a progress bar under each.
Note that if you have purchased apps with a different iTunes Store account from the Apple ID you’re using for iCloud, you will simply be prompted to enter your password for those additional accounts in order to download the necessary content. If you had media content on your iPhone that came from sources other than the iTunes Store (e.g. your own ripped CDs), you will need to sync with iTunes once the iCloud restore completes in order to transfer that content over to your new iPhone; your iTunes sync settings form part of the iCloud backup so you shouldn’t need to reconfigure anything in iTunes—just plug your iPhone into your computer and let it sync.
Keep in mind that this process only works if you are setting up your new iPhone from scratch or willing to erase everything on it to restore the backup from your old iPhone. There is no way to merge backups or restore a partial backup from iCloud, so this may not be an option if you have already started using the new iPhone and have apps and data on it that you don’t want to lose. In this case, you can still re-download the apps from iTunes in the Cloud using the App Store on your device, but you will not be able to bring over any of your data unless the apps themselves provide their own cloud storage, backup/restore or import/export options.