They would have to be part of a Family Sharing group. You don't necessarily have to be the Organizer but read the support documents about Organizer payment guarantee responsibility.
How Family Sharing works - Apple Support
How to set up Family Sharing on your iPhone, iPad, or Mac - Apple Support
Share purchases with others in your Family Sharing group [on a Mac]
Share purchases with others in your Family Sharing group on Mac - Apple Support
Share subscriptions and iCloud storage with family members on iPhone
Share Apple and App Store subscriptions with family members on iPhone - Apple Support
This support article tells you how to add a family member to your subscriptions from Apple --> Add a family member to your shared subscriptions - Apple Support Eligible subscriptions are automatically shared with your family members. This article tells you what types of content you can share with your Family Sharing group —> What types of content can I share with my family? - Apple Support
For others: Read this support article about how to download apps and content that your family members purchased - Find content purchased by members in your Family Sharing group on your iPhone or iPad - Apple Support
If you already set up Family Sharing
After you set up Family Sharing, eligible subscriptions are automatically shared with your family members. If your family members can't access a subscription:
1. On your iPhone or iPad, open the Settings app, then tap your name.
2. Tap Subscriptions.
3. Scroll down and tap Manage Family Access.
4. Turn on Share Eligible Subscriptions.
If you haven't set up Family Sharing
1. On your iPhone or iPad, open the Settings app.
2. Tap your name, tap Family, then tap Continue.
3. Follow the onscreen instructions to set up your Family Sharing group and invite your family members.