Q: i already synced my iphone to one computer i would like to sync it to a different computer

Hello there, Tinker_tiff.

It sounds like you need to transfer your iTunes Store purchases from your iPhone to a new computer, for the first time. The following Knowledge Base article provides steps and additional links on how to transfer your purchases to your computer:

Redownload or transfer your iTunes Store purchases from an iPhone, iPad, or iPod to a computer

The easiest way to add past iTunes Store purchases to your iOS device is to redownload them from iTunes in the Cloud.

You can also transfer your purchases from your device to your computer.

Transfer your purchases to your computer

Before you transfer your purchases, make sure that your computer is authorized with the same Apple ID you used to make the purchases. Learn how to authorize your computer using iTunes.

If you purchased content from the iTunes Store on your device using multiple Apple IDs, you'll need to authorize your computer for each one.

To transfer purchases from your device to a computer:

1. Connect your device to the computer. Wait for its icon to appear in iTunes.
   
2. Go to File > Devices.
   If you're using iTunes for Windows and can't see the menu bar, learn how to turn on iTunes menus in Windows.
3. Choose Transfer Purchases from [device name].

​​This feature works only for content bought from the iTunes Store. If your device is using iOS 9 or later, apps you download don’t transfer to iTunes. Any items that you imported from audio CDs or received from other sources won't copy from your device to the iTunes library. However, all podcasts from your device's Podcasts app and copies of all PDFs and books from your device's iBooks app will transfer to your computer. Learn how to transfer media to your iTunes library.

Learn more

Learn how to move your music to a new computer.

A note about copyright

iTunes software may be used to reproduce materials. It's licensed to you only for reproduction of non-copyrighted materials, materials in which you own the copyright, or materials you're authorized or legally permitted to reproduce. If you're uncertain about your right to copy any material, you should contact your legal advisor. See the iTunes Store Terms of Service for additional information.

Thanks for reaching out to Apple Support Communities.

Cheers.