The multiply line option in Sales Order Entry/Maintenance - Lines Tab under the More Options drop down has been renamed to Multiply/Divide Line Quantities and allows users to multiply or divide all quantities on a sales order or quote by a certain value. This can be useful when quoting a customer for a group of items, and they accept the quote and want multiples of the quote or where you quote multiple groups of items and they only want a portion.
Please refer to Multiply/Divide Line Quantities for more information.