How do I log in to my Apple Music account on my iPad without having to start a whole new plan?

Hi KiaraT_,

Thanks for posting in Apple Support Communities.

We understand that you want to sign in to Apple Music without starting a new plan. If you have an active Apple Music plan, sign in with your Apple ID in Settings.

Sign in with your Apple ID

"Sign in on your iPhone, iPad, or iPod touch

1. Open the Settings app.
2. Tap Sign in to your [device].
3. Enter your Apple ID and password.
4. If prompted, enter the six-digit verification code sent to your trusted device or phone number and complete sign in."

Regards.