Food Assistance for Kids and Families During COVID-19 Act of 2020 This bill modifies food and nutrition programs of the Department of Agriculture (USDA) to address COVID-19 (i.e., coronavirus disease 2019). The bill modifies the Supplemental Nutrition Assistance Program (SNAP, formerly known as the food stamp program) to require USDA to (1) notify retailers of the existing opportunities through which they can deliver groceries to SNAP participants; and (2) authorize public-private partnerships between itself, authorized SNAP retailers, and community-based organizations to support grocery delivery during the COVID-19 national emergency. The bill provides funding for USDA to support grocery delivery for SNAP participants who are seniors, immunocompromised individuals, or other individuals who are unable to travel safely to a grocery store. Additionally, the bill (1) extends the certification period under the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) for infants to two years, instead of the current one year; and (2) authorizes states to increase the certification time under WIC for breastfeeding and non-breastfeeding women to two years postpartum. The bill also allows any federal agency charged with the administration of a federal assistance program to modify or waive administrative conditions during an emergency.