What are Transaction References?
Each type of transaction, for example, a check payment, sales order, movement order needs a unique reference number, which must be set up before the transaction can be processed. You can define the layout and content of transaction references depending on your requirements. For example, if you store  a check number as a transaction reference you may need part of the reference number to include the Operator Id, date or a specific number.
Once you have created a transaction reference, you can include it in the document format where it is to be used, so that the document uses the correct formats. For example, the document format for a sales order may include the transaction reference for the sales order. Default references are held in the Purchase Business Setup, Sales Business Setup and Inventory Business Setup. The defaults are used if there are none defined on the document format.
Transaction references can contain up to four parts which are each defined separately. It is not mandatory that all four parts are used.
You can use analysis to change the contents of any or all parts, depending on the characteristics of a transaction. See What are Analysis Dimensions and Codes? for more information. For example, a different prefix for each warehouse. If you use a code which exists on an order line, the code on the first line processed is used.
You can use transaction references in conjunction with number streams, which are used to define the next available number in a transaction reference sequence.