We have a family subscription but it doesn't shows in my music app and asks me to buy my own subscription

Thanks for reaching out iffisays,

It sounds like you're having trouble using a Family subscription of Apple Music. We can help.

Let's start by making sure you are actually part of the Family Share group, since that would make the most sense why you don't see an option. Check out these steps to Add a member to a Family Sharing group on iPhone:

Add a family member with an Apple ID

The organizer of the Family Sharing group can add a family member who has their own Apple ID.

1. Go to Settings  > [your name] > Family Sharing, then tap  in the upper-right corner.

2. Tap Invite Others, then follow the onscreen instructions.

3. You can send the invitation using AirDrop, Messages, or Mail. If you’re near the family member, you can also tap Invite in Person and ask the family member to enter their Apple ID and password on your device.

Hope that helps.

Take care.