At this time, Balance is not compatible with Apple or Google Family Sharing and does not include multi-user functionality.
For now, however, the person you want to share your account with can download Balance and take advantage of the free year promotion that is available to all new Balance members.
Alternatively, they could create a free account, which will allow them to use the Foundations 10-day plan or the Advanced 10-day plan along with some of the Single meditations.