I was added to family sharing for Apple Music but I still can’t access from my device I use an iPhone 12 and it’s still asking me to subscribe

Hi EAM86,

Welcome to the Apple Community.

The person who added you to family sharing would likely have invited you to join, when setting it up.

In order to access Family Sharing:

You would have needed to respond to that invitation,

or

to have entered your Apple ID into their device.

If that hasn't happened ... you might want to check with the person who set up family sharing.

Also: You might want to show them the article below.

____________________________________________________________________________

Apple Support's article:

"Set up Family Sharing"

Says:

Invite people to join your family

If you haven't already, you can create an Apple ID for a child and add them to your group.

If your family member already has an Apple ID, use the steps below to add someone to your family group. 

You can be a part of only one family at a time.

If your family member is with you, they can enter their Apple ID password on your device to accept the invitation.

You can also send them an invitation, and they can accept from their device.

On your iPhone, iPad, or iPod touch

1. 1. Go to Settings.
   2. Tap your name, then tap Family Sharing.
   3. Tap Add Member.
   4. Enter your family member's name or email address and follow the onscreen instructions.
   5. Choose whether you’d like to send an invitation via Messages or to invite them in person. Then follow the onscreen instructions.

And

See if your family member accepted the invitation

After you send the invitation, you can check its status under the person's name.

Complete article: https://support.apple.com/en-us/HT201088

All the best :-)