School Modernization and Efficient Access to Lunches for Students Act of 2021 or the School MEALS Act of 2021 This bill establishes programs and revises requirements relating to direct certification processes for the National School Lunch Program. Direct certification allows schools to use data matching procedures to approve school meals without the need for applications for children who receive assistance under other programs, such as the Supplemental Nutrition Assistance Program (SNAP, formerly known as the food stamp program). Specifically, the bill directs the Department of Agriculture to provide grants and technical assistance for states and tribal organizations to improve their direct certification processes, including with respect to children who receive assistance under a food distribution program on Indian reservations. The bill also expands the time frame for schools to elect and gather eligibility data for the Community Eligibility Provision that permits schools in high-poverty areas to serve free meals to all enrolled students without the need for applications.