I need help adding family members to my microsoft 365 personal

Microsoft 365 Personal cannot be shared with family members. It is licensed for one subscriber only, although that subscriber can install the apps on multiple devices owned by that same person.

To share Microsoft 365 benefits (apps and OneDrive storage) with family members, a Microsoft 365 Family or Microsoft 365 Premium subscription is required. With those subscriptions, up to five other people in the family group can be added and share the subscription.

If sharing with family is needed, switch from Microsoft 365 Personal to Microsoft 365 Family, then use the subscription sharing features to invite family members.

References:

• Share your Microsoft 365 Family or Premium subscription
• How to share your Microsoft 365 Family subscription
• Manage Microsoft 365 Family subscription sharing
• how to download microsoft office 365 from subscription with multiple installs - Microsoft Q&A