Return filing periodicity determines distinct filing frequencies and invalidity of unpaid self-assessed returns affecting invoice matching. A common periodicity of return filing applies by taxpayer class; returns unpaid for self-assessed tax are invalid and excluded from invoice matching and inter-governmental fund settlement. Distinct return types and filing cadences are set for outward and inward supplies, monthly and quarterly filers, compounding taxpayers, non-resident taxpayers, input service distributors and TDS deductors, with continuous maintenance of ITC, cash and tax ledgers and a requirement for online filing with offline upload permitted.