Supporting America's Caregivers and Families Act This bill reauthorizes through FY2024, and modifies, programs for family caregivers of older adults, including with respect to caregiver assessment tools and capacity-building for aging networks. It also establishes the National Family Caregiver Resource and Technical Assistance Center to support state and local agencies, community-based providers, and family caregivers. Specifically, the Administration on Aging must develop a strategy to increase the use of caregiver assessment tools and conduct a study that addresses, among other topics, the feasibility of mandating the use of such tools. Additionally, states must report on the mechanisms they use to assess the needs of caregivers. The bill also provides statutory authority for certain activities to build the business acumen and related skills of aging networks to increase their capacity to serve older adults and caregivers.