The ‘Line Items’ contain information relating to account number, amount, debit/credit, tax code, amount, etc. SAP allows a maximum of 999 line items in a single document. Besides the one entered by you during an document entry, the system may also create its own line items called ‘system generated line items’ such as tax deductions, etc. Irrespective of the number of line items entered, ensure that the total of these is always zero (that is, total debits should equal total credits). Otherwise, the system will not allow you to post the document.