Hey leeannefromauburn,
We'd be happy to help out. If the Apple Music promo you're referring to is for an individual plan, it wouldn't be shareable with your family, however if it's a Family subscription, you could certainly do so.
For more help with changing your subscription to ensure it's able to be shared with your family, follow these steps:
Switch your subscription plan on your iPhone or iPad
1. Open the Settings app.
2. Tap your name, then tap Subscriptions.
3. Tap the name of the subscription that you want to change.
4. Tap See All Plans, then follow the onscreen instructions to complete your purchase.
5. If you chose a subscription that you can share with family, turn on Share with Family. (Don't see Share with Family? Set up Family Sharing or join a family, then return to your list of subscriptions and turn on Share with Family.) If you don't want to share the subscription with your family, turn off Share with Family.
This is outlined further here: How to switch to a different subscription plan - Apple Support
We hope this helps out. For more info on Verizon's promo though you should contact them directly.
Take care!