If you need to access your iTunes account from another device, you need to log into that device, with your account.
Just remember, that you’ll have to switch back to the other account each time you need to update or download an app:
- Launch the settings app on your iPhone or iPad
- Tap on “iTunes & App Stores”
- Tap on your Apple ID
- Tap on “Sign Out”
- Then on the same scree, tap on “Sign In”
- Enter a different Apple Id and Password
- Tap on “Sign In”
