This wikiHow teaches you how to log into iTunes using your Apple ID. You can do this on the desktop or mobile version of iTunes. You'll need to create an Apple ID first if you don't have one.
Step
Method 1 of 2: On a Desktop Computer
Step 1. Launch iTunes
Double-click the iTunes icon, which is a colorful musical note on a white background.
Step 2. Click Account. It's at the top of the iTunes window (on Windows) or screen (Mac)
This will bring up a drop-down menu.
Step 3. Click Sign In…
This option is in the middle of the drop-down menu. A pop-up window will be displayed.
If another Apple ID is signed in, first click Sign Out, then click Sign In.
Step 4. Type in your Apple ID email address
Enter your Apple ID email address in the "Apple ID" text box at the top of the pop-up window.
Step 5. Type in the Apple ID password
Enter the password used to log into your Apple ID account in the "Password" text box in the pop-up window.
Step 6. Click Sign In at the bottom of the window
Doing so will sign you in to your Apple ID account.
Any iTunes purchases made using this account will be available in iTunes when it's finished syncing
Method 2 of 2: On Mobile Devices
Step 1. Open Settings
on iPhone.
Tap the Settings icon, which is a gray box with a gear in it.
Step 2. Tap Sign in to your iPhone
It's at the top of the screen.
If your name and photo are shown here, you're signed in to your Apple ID on your iPhone
Step 3. Enter your Apple ID email address
Tap the "Apple ID" text box, then enter your Apple ID email address.
Step 4. Tap Next in the top right corner
Step 5. Type in the Apple ID password
Tap the "Password" text box, then type the password you use to log into your Apple ID account.
Step 6. Tap Next which is in the top right corner
Step 7. Type in your iPhone passcode when prompted
Enter the passcode used to unlock iPhone. This will confirm your login and add the iTunes content for your account to the iTunes library.
